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//                For Open Source Computer Vision Library
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/* ////////////////////////////////////////////////////////////////////
//
//  Geometrical transforms on images and matrices: rotation, zoom etc.
//
// */

#include "precomp.hpp"
#include "opencl_kernels_imgproc.hpp"
#include "hal_replacement.hpp"

#include "opencv2/core/openvx/ovx_defs.hpp"
#include "resize.hpp"

using namespace cv;

namespace cv
{

/************** interpolation formulas and tables ***************/

const int INTER_RESIZE_COEF_BITS=11;
const int INTER_RESIZE_COEF_SCALE=1 << INTER_RESIZE_COEF_BITS;

static inline void interpolateCubic( float x, float* coeffs )
{
    const float A = -0.75f;

    coeffs[0] = ((A*(x + 1) - 5*A)*(x + 1) + 8*A)*(x + 1) - 4*A;
    coeffs[1] = ((A + 2)*x - (A + 3))*x*x + 1;
    coeffs[2] = ((A + 2)*(1 - x) - (A + 3))*(1 - x)*(1 - x) + 1;
    coeffs[3] = 1.f - coeffs[0] - coeffs[1] - coeffs[2];
}

static inline void interpolateLanczos4( float x, float* coeffs )
{
    static const double s45 = 0.70710678118654752440084436210485;
    static const double cs[][2]=
    {{1, 0}, {-s45, -s45}, {0, 1}, {s45, -s45}, {-1, 0}, {s45, s45}, {0, -1}, {-s45, s45}};

    if( x < FLT_EPSILON )
    {
        for( int i = 0; i < 8; i++ )
            coeffs[i] = 0;
        coeffs[3] = 1;
        return;
    }

    float sum = 0;
    double y0=-(x+3)*CV_PI*0.25, s0 = sin(y0), c0=cos(y0);
    for(int i = 0; i < 8; i++ )
    {
        double y = -(x+3-i)*CV_PI*0.25;
        coeffs[i] = (float)((cs[i][0]*s0 + cs[i][1]*c0)/(y*y));
        sum += coeffs[i];
    }

    sum = 1.f/sum;
    for(int i = 0; i < 8; i++ )
        coeffs[i] *= sum;
}

template<typename ST, typename DT> struct Cast
{
    typedef ST type1;
    typedef DT rtype;

    DT operator()(ST val) const { return saturate_cast<DT>(val); }
};

template<typename ST, typename DT, int bits> struct FixedPtCast
{
    typedef ST type1;
    typedef DT rtype;
    enum { SHIFT = bits, DELTA = 1 << (bits-1) };

    DT operator()(ST val) const { return saturate_cast<DT>((val + DELTA)>>SHIFT); }
};

/****************************************************************************************\
*                                         Resize                                         *
\****************************************************************************************/

class resizeNNInvoker :
    public ParallelLoopBody
{
public:
    resizeNNInvoker(const Mat& _src, Mat &_dst, int *_x_ofs, int _pix_size4, double _ify) :
        ParallelLoopBody(), src(_src), dst(_dst), x_ofs(_x_ofs), pix_size4(_pix_size4),
        ify(_ify)
    {
    }

    virtual void operator() (const Range& range) const
    {
        Size ssize = src.size(), dsize = dst.size();
        int y, x, pix_size = (int)src.elemSize();

        for( y = range.start; y < range.end; y++ )
        {
            uchar* D = dst.data + dst.step*y;
            int sy = std::min(cvFloor(y*ify), ssize.height-1);
            const uchar* S = src.ptr(sy);

            switch( pix_size )
            {
            case 1:
                for( x = 0; x <= dsize.width - 2; x += 2 )
                {
                    uchar t0 = S[x_ofs[x]];
                    uchar t1 = S[x_ofs[x+1]];
                    D[x] = t0;
                    D[x+1] = t1;
                }

                for( ; x < dsize.width; x++ )
                    D[x] = S[x_ofs[x]];
                break;
            case 2:
                for( x = 0; x < dsize.width; x++ )
                    *(ushort*)(D + x*2) = *(ushort*)(S + x_ofs[x]);
                break;
            case 3:
                for( x = 0; x < dsize.width; x++, D += 3 )
                {
                    const uchar* _tS = S + x_ofs[x];
                    D[0] = _tS[0]; D[1] = _tS[1]; D[2] = _tS[2];
                }
                break;
            case 4:
                for( x = 0; x < dsize.width; x++ )
                    *(int*)(D + x*4) = *(int*)(S + x_ofs[x]);
                break;
            case 6:
                for( x = 0; x < dsize.width; x++, D += 6 )
                {
                    const ushort* _tS = (const ushort*)(S + x_ofs[x]);
                    ushort* _tD = (ushort*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            case 8:
                for( x = 0; x < dsize.width; x++, D += 8 )
                {
                    const int* _tS = (const int*)(S + x_ofs[x]);
                    int* _tD = (int*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1];
                }
                break;
            case 12:
                for( x = 0; x < dsize.width; x++, D += 12 )
                {
                    const int* _tS = (const int*)(S + x_ofs[x]);
                    int* _tD = (int*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            default:
                for( x = 0; x < dsize.width; x++, D += pix_size )
                {
                    const int* _tS = (const int*)(S + x_ofs[x]);
                    int* _tD = (int*)D;
                    for( int k = 0; k < pix_size4; k++ )
                        _tD[k] = _tS[k];
                }
            }
        }
    }

private:
    const Mat src;
    Mat dst;
    int* x_ofs, pix_size4;
    double ify;

    resizeNNInvoker(const resizeNNInvoker&);
    resizeNNInvoker& operator=(const resizeNNInvoker&);
};

static void
resizeNN( const Mat& src, Mat& dst, double fx, double fy )
{
    Size ssize = src.size(), dsize = dst.size();
    AutoBuffer<int> _x_ofs(dsize.width);
    int* x_ofs = _x_ofs;
    int pix_size = (int)src.elemSize();
    int pix_size4 = (int)(pix_size / sizeof(int));
    double ifx = 1./fx, ify = 1./fy;
    int x;

    for( x = 0; x < dsize.width; x++ )
    {
        int sx = cvFloor(x*ifx);
        x_ofs[x] = std::min(sx, ssize.width-1)*pix_size;
    }

    Range range(0, dsize.height);
#if CV_TRY_AVX2
    if(CV_CPU_HAS_SUPPORT_AVX2 && ((pix_size == 2) || (pix_size == 4)))
    {
        if(pix_size == 2)
            opt_AVX2::resizeNN2_AVX2(range, src, dst, x_ofs, pix_size4, ify);
        else
            opt_AVX2::resizeNN4_AVX2(range, src, dst, x_ofs, pix_size4, ify);
    }
    else
#endif
#if CV_TRY_SSE4_1
    if(CV_CPU_HAS_SUPPORT_SSE4_1 && ((pix_size == 2) || (pix_size == 4)))
    {
        if(pix_size == 2)
            opt_SSE4_1::resizeNN2_SSE4_1(range, src, dst, x_ofs, pix_size4, ify);
        else
            opt_SSE4_1::resizeNN4_SSE4_1(range, src, dst, x_ofs, pix_size4, ify);
    }
    else
#endif
    {
        resizeNNInvoker invoker(src, dst, x_ofs, pix_size4, ify);
        parallel_for_(range, invoker, dst.total()/(double)(1<<16));
    }
}


struct VResizeNoVec
{
    int operator()(const uchar**, uchar*, const uchar*, int ) const { return 0; }
};

struct HResizeNoVec
{
    int operator()(const uchar**, uchar**, int, const int*,
        const uchar*, int, int, int, int, int) const { return 0; }
};

#if CV_SSE2

struct VResizeLinearVec_32s8u
{
    int operator()(const uchar** _src, uchar* dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE2) )
            return 0;

        const int** src = (const int**)_src;
        const short* beta = (const short*)_beta;
        const int *S0 = src[0], *S1 = src[1];
        int x = 0;
        __m128i b0 = _mm_set1_epi16(beta[0]), b1 = _mm_set1_epi16(beta[1]);
        __m128i delta = _mm_set1_epi16(2);

        if( (((size_t)S0|(size_t)S1)&15) == 0 )
            for( ; x <= width - 16; x += 16 )
            {
                __m128i x0, x1, x2, y0, y1, y2;
                x0 = _mm_load_si128((const __m128i*)(S0 + x));
                x1 = _mm_load_si128((const __m128i*)(S0 + x + 4));
                y0 = _mm_load_si128((const __m128i*)(S1 + x));
                y1 = _mm_load_si128((const __m128i*)(S1 + x + 4));
                x0 = _mm_packs_epi32(_mm_srai_epi32(x0, 4), _mm_srai_epi32(x1, 4));
                y0 = _mm_packs_epi32(_mm_srai_epi32(y0, 4), _mm_srai_epi32(y1, 4));

                x1 = _mm_load_si128((const __m128i*)(S0 + x + 8));
                x2 = _mm_load_si128((const __m128i*)(S0 + x + 12));
                y1 = _mm_load_si128((const __m128i*)(S1 + x + 8));
                y2 = _mm_load_si128((const __m128i*)(S1 + x + 12));
                x1 = _mm_packs_epi32(_mm_srai_epi32(x1, 4), _mm_srai_epi32(x2, 4));
                y1 = _mm_packs_epi32(_mm_srai_epi32(y1, 4), _mm_srai_epi32(y2, 4));

                x0 = _mm_adds_epi16(_mm_mulhi_epi16( x0, b0 ), _mm_mulhi_epi16( y0, b1 ));
                x1 = _mm_adds_epi16(_mm_mulhi_epi16( x1, b0 ), _mm_mulhi_epi16( y1, b1 ));

                x0 = _mm_srai_epi16(_mm_adds_epi16(x0, delta), 2);
                x1 = _mm_srai_epi16(_mm_adds_epi16(x1, delta), 2);
                _mm_storeu_si128( (__m128i*)(dst + x), _mm_packus_epi16(x0, x1));
            }
        else
            for( ; x <= width - 16; x += 16 )
            {
                __m128i x0, x1, x2, y0, y1, y2;
                x0 = _mm_loadu_si128((const __m128i*)(S0 + x));
                x1 = _mm_loadu_si128((const __m128i*)(S0 + x + 4));
                y0 = _mm_loadu_si128((const __m128i*)(S1 + x));
                y1 = _mm_loadu_si128((const __m128i*)(S1 + x + 4));
                x0 = _mm_packs_epi32(_mm_srai_epi32(x0, 4), _mm_srai_epi32(x1, 4));
                y0 = _mm_packs_epi32(_mm_srai_epi32(y0, 4), _mm_srai_epi32(y1, 4));

                x1 = _mm_loadu_si128((const __m128i*)(S0 + x + 8));
                x2 = _mm_loadu_si128((const __m128i*)(S0 + x + 12));
                y1 = _mm_loadu_si128((const __m128i*)(S1 + x + 8));
                y2 = _mm_loadu_si128((const __m128i*)(S1 + x + 12));
                x1 = _mm_packs_epi32(_mm_srai_epi32(x1, 4), _mm_srai_epi32(x2, 4));
                y1 = _mm_packs_epi32(_mm_srai_epi32(y1, 4), _mm_srai_epi32(y2, 4));

                x0 = _mm_adds_epi16(_mm_mulhi_epi16( x0, b0 ), _mm_mulhi_epi16( y0, b1 ));
                x1 = _mm_adds_epi16(_mm_mulhi_epi16( x1, b0 ), _mm_mulhi_epi16( y1, b1 ));

                x0 = _mm_srai_epi16(_mm_adds_epi16(x0, delta), 2);
                x1 = _mm_srai_epi16(_mm_adds_epi16(x1, delta), 2);
                _mm_storeu_si128( (__m128i*)(dst + x), _mm_packus_epi16(x0, x1));
            }

        for( ; x < width - 4; x += 4 )
        {
            __m128i x0, y0;
            x0 = _mm_srai_epi32(_mm_loadu_si128((const __m128i*)(S0 + x)), 4);
            y0 = _mm_srai_epi32(_mm_loadu_si128((const __m128i*)(S1 + x)), 4);
            x0 = _mm_packs_epi32(x0, x0);
            y0 = _mm_packs_epi32(y0, y0);
            x0 = _mm_adds_epi16(_mm_mulhi_epi16(x0, b0), _mm_mulhi_epi16(y0, b1));
            x0 = _mm_srai_epi16(_mm_adds_epi16(x0, delta), 2);
            x0 = _mm_packus_epi16(x0, x0);
            *(int*)(dst + x) = _mm_cvtsi128_si32(x0);
        }

        return x;
    }
};


template<int shiftval> struct VResizeLinearVec_32f16
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE2) )
            return 0;

        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1];
        ushort* dst = (ushort*)_dst;
        int x = 0;

        __m128 b0 = _mm_set1_ps(beta[0]), b1 = _mm_set1_ps(beta[1]);
        __m128i preshift = _mm_set1_epi32(shiftval);
        __m128i postshift = _mm_set1_epi16((short)shiftval);

        if( (((size_t)S0|(size_t)S1)&15) == 0 )
            for( ; x <= width - 16; x += 16 )
            {
                __m128 x0, x1, y0, y1;
                __m128i t0, t1, t2;
                x0 = _mm_load_ps(S0 + x);
                x1 = _mm_load_ps(S0 + x + 4);
                y0 = _mm_load_ps(S1 + x);
                y1 = _mm_load_ps(S1 + x + 4);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));
                t0 = _mm_add_epi32(_mm_cvtps_epi32(x0), preshift);
                t2 = _mm_add_epi32(_mm_cvtps_epi32(x1), preshift);
                t0 = _mm_add_epi16(_mm_packs_epi32(t0, t2), postshift);

                x0 = _mm_load_ps(S0 + x + 8);
                x1 = _mm_load_ps(S0 + x + 12);
                y0 = _mm_load_ps(S1 + x + 8);
                y1 = _mm_load_ps(S1 + x + 12);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));
                t1 = _mm_add_epi32(_mm_cvtps_epi32(x0), preshift);
                t2 = _mm_add_epi32(_mm_cvtps_epi32(x1), preshift);
                t1 = _mm_add_epi16(_mm_packs_epi32(t1, t2), postshift);

                _mm_storeu_si128( (__m128i*)(dst + x), t0);
                _mm_storeu_si128( (__m128i*)(dst + x + 8), t1);
            }
        else
            for( ; x <= width - 16; x += 16 )
            {
                __m128 x0, x1, y0, y1;
                __m128i t0, t1, t2;
                x0 = _mm_loadu_ps(S0 + x);
                x1 = _mm_loadu_ps(S0 + x + 4);
                y0 = _mm_loadu_ps(S1 + x);
                y1 = _mm_loadu_ps(S1 + x + 4);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));
                t0 = _mm_add_epi32(_mm_cvtps_epi32(x0), preshift);
                t2 = _mm_add_epi32(_mm_cvtps_epi32(x1), preshift);
                t0 = _mm_add_epi16(_mm_packs_epi32(t0, t2), postshift);

                x0 = _mm_loadu_ps(S0 + x + 8);
                x1 = _mm_loadu_ps(S0 + x + 12);
                y0 = _mm_loadu_ps(S1 + x + 8);
                y1 = _mm_loadu_ps(S1 + x + 12);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));
                t1 = _mm_add_epi32(_mm_cvtps_epi32(x0), preshift);
                t2 = _mm_add_epi32(_mm_cvtps_epi32(x1), preshift);
                t1 = _mm_add_epi16(_mm_packs_epi32(t1, t2), postshift);

                _mm_storeu_si128( (__m128i*)(dst + x), t0);
                _mm_storeu_si128( (__m128i*)(dst + x + 8), t1);
            }

        for( ; x < width - 4; x += 4 )
        {
            __m128 x0, y0;
            __m128i t0;
            x0 = _mm_loadu_ps(S0 + x);
            y0 = _mm_loadu_ps(S1 + x);

            x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
            t0 = _mm_add_epi32(_mm_cvtps_epi32(x0), preshift);
            t0 = _mm_add_epi16(_mm_packs_epi32(t0, t0), postshift);
            _mm_storel_epi64( (__m128i*)(dst + x), t0);
        }

        return x;
    }
};

typedef VResizeLinearVec_32f16<SHRT_MIN> VResizeLinearVec_32f16u;
typedef VResizeLinearVec_32f16<0> VResizeLinearVec_32f16s;

struct VResizeLinearVec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE) )
            return 0;

        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1];
        float* dst = (float*)_dst;
        int x = 0;

        __m128 b0 = _mm_set1_ps(beta[0]), b1 = _mm_set1_ps(beta[1]);

        if( (((size_t)S0|(size_t)S1)&15) == 0 )
            for( ; x <= width - 8; x += 8 )
            {
                __m128 x0, x1, y0, y1;
                x0 = _mm_load_ps(S0 + x);
                x1 = _mm_load_ps(S0 + x + 4);
                y0 = _mm_load_ps(S1 + x);
                y1 = _mm_load_ps(S1 + x + 4);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));

                _mm_storeu_ps( dst + x, x0);
                _mm_storeu_ps( dst + x + 4, x1);
            }
        else
            for( ; x <= width - 8; x += 8 )
            {
                __m128 x0, x1, y0, y1;
                x0 = _mm_loadu_ps(S0 + x);
                x1 = _mm_loadu_ps(S0 + x + 4);
                y0 = _mm_loadu_ps(S1 + x);
                y1 = _mm_loadu_ps(S1 + x + 4);

                x0 = _mm_add_ps(_mm_mul_ps(x0, b0), _mm_mul_ps(y0, b1));
                x1 = _mm_add_ps(_mm_mul_ps(x1, b0), _mm_mul_ps(y1, b1));

                _mm_storeu_ps( dst + x, x0);
                _mm_storeu_ps( dst + x + 4, x1);
            }

        return x;
    }
};


struct VResizeCubicVec_32s8u
{
    int operator()(const uchar** _src, uchar* dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE2) )
            return 0;

        const int** src = (const int**)_src;
        const short* beta = (const short*)_beta;
        const int *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        int x = 0;
        float scale = 1.f/(INTER_RESIZE_COEF_SCALE*INTER_RESIZE_COEF_SCALE);
        __m128 b0 = _mm_set1_ps(beta[0]*scale), b1 = _mm_set1_ps(beta[1]*scale),
            b2 = _mm_set1_ps(beta[2]*scale), b3 = _mm_set1_ps(beta[3]*scale);

        if( (((size_t)S0|(size_t)S1|(size_t)S2|(size_t)S3)&15) == 0 )
            for( ; x <= width - 8; x += 8 )
            {
                __m128i x0, x1, y0, y1;
                __m128 s0, s1, f0, f1;
                x0 = _mm_load_si128((const __m128i*)(S0 + x));
                x1 = _mm_load_si128((const __m128i*)(S0 + x + 4));
                y0 = _mm_load_si128((const __m128i*)(S1 + x));
                y1 = _mm_load_si128((const __m128i*)(S1 + x + 4));

                s0 = _mm_mul_ps(_mm_cvtepi32_ps(x0), b0);
                s1 = _mm_mul_ps(_mm_cvtepi32_ps(x1), b0);
                f0 = _mm_mul_ps(_mm_cvtepi32_ps(y0), b1);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(y1), b1);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);

                x0 = _mm_load_si128((const __m128i*)(S2 + x));
                x1 = _mm_load_si128((const __m128i*)(S2 + x + 4));
                y0 = _mm_load_si128((const __m128i*)(S3 + x));
                y1 = _mm_load_si128((const __m128i*)(S3 + x + 4));

                f0 = _mm_mul_ps(_mm_cvtepi32_ps(x0), b2);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(x1), b2);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);
                f0 = _mm_mul_ps(_mm_cvtepi32_ps(y0), b3);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(y1), b3);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);

                x0 = _mm_cvtps_epi32(s0);
                x1 = _mm_cvtps_epi32(s1);

                x0 = _mm_packs_epi32(x0, x1);
                _mm_storel_epi64( (__m128i*)(dst + x), _mm_packus_epi16(x0, x0));
            }
        else
            for( ; x <= width - 8; x += 8 )
            {
                __m128i x0, x1, y0, y1;
                __m128 s0, s1, f0, f1;
                x0 = _mm_loadu_si128((const __m128i*)(S0 + x));
                x1 = _mm_loadu_si128((const __m128i*)(S0 + x + 4));
                y0 = _mm_loadu_si128((const __m128i*)(S1 + x));
                y1 = _mm_loadu_si128((const __m128i*)(S1 + x + 4));

                s0 = _mm_mul_ps(_mm_cvtepi32_ps(x0), b0);
                s1 = _mm_mul_ps(_mm_cvtepi32_ps(x1), b0);
                f0 = _mm_mul_ps(_mm_cvtepi32_ps(y0), b1);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(y1), b1);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);

                x0 = _mm_loadu_si128((const __m128i*)(S2 + x));
                x1 = _mm_loadu_si128((const __m128i*)(S2 + x + 4));
                y0 = _mm_loadu_si128((const __m128i*)(S3 + x));
                y1 = _mm_loadu_si128((const __m128i*)(S3 + x + 4));

                f0 = _mm_mul_ps(_mm_cvtepi32_ps(x0), b2);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(x1), b2);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);
                f0 = _mm_mul_ps(_mm_cvtepi32_ps(y0), b3);
                f1 = _mm_mul_ps(_mm_cvtepi32_ps(y1), b3);
                s0 = _mm_add_ps(s0, f0);
                s1 = _mm_add_ps(s1, f1);

                x0 = _mm_cvtps_epi32(s0);
                x1 = _mm_cvtps_epi32(s1);

                x0 = _mm_packs_epi32(x0, x1);
                _mm_storel_epi64( (__m128i*)(dst + x), _mm_packus_epi16(x0, x0));
            }

        return x;
    }
};


template<int shiftval> struct VResizeCubicVec_32f16
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE2) )
            return 0;

        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        ushort* dst = (ushort*)_dst;
        int x = 0;
        __m128 b0 = _mm_set1_ps(beta[0]), b1 = _mm_set1_ps(beta[1]),
            b2 = _mm_set1_ps(beta[2]), b3 = _mm_set1_ps(beta[3]);
        __m128i preshift = _mm_set1_epi32(shiftval);
        __m128i postshift = _mm_set1_epi16((short)shiftval);

        for( ; x <= width - 8; x += 8 )
        {
            __m128 x0, x1, y0, y1, s0, s1;
            __m128i t0, t1;
            x0 = _mm_loadu_ps(S0 + x);
            x1 = _mm_loadu_ps(S0 + x + 4);
            y0 = _mm_loadu_ps(S1 + x);
            y1 = _mm_loadu_ps(S1 + x + 4);

            s0 = _mm_mul_ps(x0, b0);
            s1 = _mm_mul_ps(x1, b0);
            y0 = _mm_mul_ps(y0, b1);
            y1 = _mm_mul_ps(y1, b1);
            s0 = _mm_add_ps(s0, y0);
            s1 = _mm_add_ps(s1, y1);

            x0 = _mm_loadu_ps(S2 + x);
            x1 = _mm_loadu_ps(S2 + x + 4);
            y0 = _mm_loadu_ps(S3 + x);
            y1 = _mm_loadu_ps(S3 + x + 4);

            x0 = _mm_mul_ps(x0, b2);
            x1 = _mm_mul_ps(x1, b2);
            y0 = _mm_mul_ps(y0, b3);
            y1 = _mm_mul_ps(y1, b3);
            s0 = _mm_add_ps(s0, x0);
            s1 = _mm_add_ps(s1, x1);
            s0 = _mm_add_ps(s0, y0);
            s1 = _mm_add_ps(s1, y1);

            t0 = _mm_add_epi32(_mm_cvtps_epi32(s0), preshift);
            t1 = _mm_add_epi32(_mm_cvtps_epi32(s1), preshift);

            t0 = _mm_add_epi16(_mm_packs_epi32(t0, t1), postshift);
            _mm_storeu_si128( (__m128i*)(dst + x), t0);
        }

        return x;
    }
};

typedef VResizeCubicVec_32f16<SHRT_MIN> VResizeCubicVec_32f16u;
typedef VResizeCubicVec_32f16<0> VResizeCubicVec_32f16s;

struct VResizeCubicVec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        if( !checkHardwareSupport(CV_CPU_SSE) )
            return 0;

        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        float* dst = (float*)_dst;
        int x = 0;
        __m128 b0 = _mm_set1_ps(beta[0]), b1 = _mm_set1_ps(beta[1]),
            b2 = _mm_set1_ps(beta[2]), b3 = _mm_set1_ps(beta[3]);

        for( ; x <= width - 8; x += 8 )
        {
            __m128 x0, x1, y0, y1, s0, s1;
            x0 = _mm_loadu_ps(S0 + x);
            x1 = _mm_loadu_ps(S0 + x + 4);
            y0 = _mm_loadu_ps(S1 + x);
            y1 = _mm_loadu_ps(S1 + x + 4);

            s0 = _mm_mul_ps(x0, b0);
            s1 = _mm_mul_ps(x1, b0);
            y0 = _mm_mul_ps(y0, b1);
            y1 = _mm_mul_ps(y1, b1);
            s0 = _mm_add_ps(s0, y0);
            s1 = _mm_add_ps(s1, y1);

            x0 = _mm_loadu_ps(S2 + x);
            x1 = _mm_loadu_ps(S2 + x + 4);
            y0 = _mm_loadu_ps(S3 + x);
            y1 = _mm_loadu_ps(S3 + x + 4);

            x0 = _mm_mul_ps(x0, b2);
            x1 = _mm_mul_ps(x1, b2);
            y0 = _mm_mul_ps(y0, b3);
            y1 = _mm_mul_ps(y1, b3);
            s0 = _mm_add_ps(s0, x0);
            s1 = _mm_add_ps(s1, x1);
            s0 = _mm_add_ps(s0, y0);
            s1 = _mm_add_ps(s1, y1);

            _mm_storeu_ps( dst + x, s0);
            _mm_storeu_ps( dst + x + 4, s1);
        }

        return x;
    }
};

#if CV_TRY_SSE4_1

struct VResizeLanczos4Vec_32f16u
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        if (CV_CPU_HAS_SUPPORT_SSE4_1) return opt_SSE4_1::VResizeLanczos4Vec_32f16u_SSE41(_src, _dst, _beta, width);
        else return 0;
    }
};

#else

typedef VResizeNoVec VResizeLanczos4Vec_32f16u;

#endif

struct VResizeLanczos4Vec_32f16s
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        short * dst = (short*)_dst;
        int x = 0;
        __m128 v_b0 = _mm_set1_ps(beta[0]), v_b1 = _mm_set1_ps(beta[1]),
               v_b2 = _mm_set1_ps(beta[2]), v_b3 = _mm_set1_ps(beta[3]),
               v_b4 = _mm_set1_ps(beta[4]), v_b5 = _mm_set1_ps(beta[5]),
               v_b6 = _mm_set1_ps(beta[6]), v_b7 = _mm_set1_ps(beta[7]);

        for( ; x <= width - 8; x += 8 )
        {
            __m128 v_dst0 = _mm_mul_ps(v_b0, _mm_loadu_ps(S0 + x));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b1, _mm_loadu_ps(S1 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b2, _mm_loadu_ps(S2 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b3, _mm_loadu_ps(S3 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b4, _mm_loadu_ps(S4 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b5, _mm_loadu_ps(S5 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b6, _mm_loadu_ps(S6 + x)));
            v_dst0 = _mm_add_ps(v_dst0, _mm_mul_ps(v_b7, _mm_loadu_ps(S7 + x)));

            __m128 v_dst1 = _mm_mul_ps(v_b0, _mm_loadu_ps(S0 + x + 4));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b1, _mm_loadu_ps(S1 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b2, _mm_loadu_ps(S2 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b3, _mm_loadu_ps(S3 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b4, _mm_loadu_ps(S4 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b5, _mm_loadu_ps(S5 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b6, _mm_loadu_ps(S6 + x + 4)));
            v_dst1 = _mm_add_ps(v_dst1, _mm_mul_ps(v_b7, _mm_loadu_ps(S7 + x + 4)));

            __m128i v_dsti0 = _mm_cvtps_epi32(v_dst0);
            __m128i v_dsti1 = _mm_cvtps_epi32(v_dst1);

            _mm_storeu_si128((__m128i *)(dst + x), _mm_packs_epi32(v_dsti0, v_dsti1));
        }

        return x;
    }
};


struct VResizeLanczos4Vec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        float* dst = (float*)_dst;
        int x = 0;

        __m128 v_b0 = _mm_set1_ps(beta[0]), v_b1 = _mm_set1_ps(beta[1]),
               v_b2 = _mm_set1_ps(beta[2]), v_b3 = _mm_set1_ps(beta[3]),
               v_b4 = _mm_set1_ps(beta[4]), v_b5 = _mm_set1_ps(beta[5]),
               v_b6 = _mm_set1_ps(beta[6]), v_b7 = _mm_set1_ps(beta[7]);

        for( ; x <= width - 4; x += 4 )
        {
            __m128 v_dst = _mm_mul_ps(v_b0, _mm_loadu_ps(S0 + x));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b1, _mm_loadu_ps(S1 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b2, _mm_loadu_ps(S2 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b3, _mm_loadu_ps(S3 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b4, _mm_loadu_ps(S4 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b5, _mm_loadu_ps(S5 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b6, _mm_loadu_ps(S6 + x)));
            v_dst = _mm_add_ps(v_dst, _mm_mul_ps(v_b7, _mm_loadu_ps(S7 + x)));

            _mm_storeu_ps(dst + x, v_dst);
        }

        return x;
    }
};


#elif CV_NEON

struct VResizeLinearVec_32s8u
{
    int operator()(const uchar** _src, uchar* dst, const uchar* _beta, int width ) const
    {
        const int** src = (const int**)_src, *S0 = src[0], *S1 = src[1];
        const short* beta = (const short*)_beta;
        int x = 0;
        int16x8_t v_b0 = vdupq_n_s16(beta[0]), v_b1 = vdupq_n_s16(beta[1]), v_delta = vdupq_n_s16(2);

        for( ; x <= width - 16; x += 16)
        {
            int32x4_t v_src00 = vshrq_n_s32(vld1q_s32(S0 + x), 4), v_src10 = vshrq_n_s32(vld1q_s32(S1 + x), 4);
            int32x4_t v_src01 = vshrq_n_s32(vld1q_s32(S0 + x + 4), 4), v_src11 = vshrq_n_s32(vld1q_s32(S1 + x + 4), 4);

            int16x8_t v_src0 = vcombine_s16(vmovn_s32(v_src00), vmovn_s32(v_src01));
            int16x8_t v_src1 = vcombine_s16(vmovn_s32(v_src10), vmovn_s32(v_src11));

            int16x8_t v_dst0 = vaddq_s16(vshrq_n_s16(vqdmulhq_s16(v_src0, v_b0), 1),
                                         vshrq_n_s16(vqdmulhq_s16(v_src1, v_b1), 1));
            v_dst0 = vshrq_n_s16(vaddq_s16(v_dst0, v_delta), 2);

            v_src00 = vshrq_n_s32(vld1q_s32(S0 + x + 8), 4);
            v_src10 = vshrq_n_s32(vld1q_s32(S1 + x + 8), 4);
            v_src01 = vshrq_n_s32(vld1q_s32(S0 + x + 12), 4);
            v_src11 = vshrq_n_s32(vld1q_s32(S1 + x + 12), 4);

            v_src0 = vcombine_s16(vmovn_s32(v_src00), vmovn_s32(v_src01));
            v_src1 = vcombine_s16(vmovn_s32(v_src10), vmovn_s32(v_src11));

            int16x8_t v_dst1 = vaddq_s16(vshrq_n_s16(vqdmulhq_s16(v_src0, v_b0), 1),
                                         vshrq_n_s16(vqdmulhq_s16(v_src1, v_b1), 1));
            v_dst1 = vshrq_n_s16(vaddq_s16(v_dst1, v_delta), 2);

            vst1q_u8(dst + x, vcombine_u8(vqmovun_s16(v_dst0), vqmovun_s16(v_dst1)));
        }

        return x;
    }
};

struct VResizeLinearVec_32f16u
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1];
        ushort* dst = (ushort*)_dst;
        int x = 0;

        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_src00 = vld1q_f32(S0 + x), v_src01 = vld1q_f32(S0 + x + 4);
            float32x4_t v_src10 = vld1q_f32(S1 + x), v_src11 = vld1q_f32(S1 + x + 4);

            float32x4_t v_dst0 = vmlaq_f32(vmulq_f32(v_src00, v_b0), v_src10, v_b1);
            float32x4_t v_dst1 = vmlaq_f32(vmulq_f32(v_src01, v_b0), v_src11, v_b1);

            vst1q_u16(dst + x, vcombine_u16(vqmovn_u32(cv_vrndq_u32_f32(v_dst0)),
                                            vqmovn_u32(cv_vrndq_u32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeLinearVec_32f16s
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1];
        short* dst = (short*)_dst;
        int x = 0;

        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_src00 = vld1q_f32(S0 + x), v_src01 = vld1q_f32(S0 + x + 4);
            float32x4_t v_src10 = vld1q_f32(S1 + x), v_src11 = vld1q_f32(S1 + x + 4);

            float32x4_t v_dst0 = vmlaq_f32(vmulq_f32(v_src00, v_b0), v_src10, v_b1);
            float32x4_t v_dst1 = vmlaq_f32(vmulq_f32(v_src01, v_b0), v_src11, v_b1);

            vst1q_s16(dst + x, vcombine_s16(vqmovn_s32(cv_vrndq_s32_f32(v_dst0)),
                                            vqmovn_s32(cv_vrndq_s32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeLinearVec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1];
        float* dst = (float*)_dst;
        int x = 0;

        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_src00 = vld1q_f32(S0 + x), v_src01 = vld1q_f32(S0 + x + 4);
            float32x4_t v_src10 = vld1q_f32(S1 + x), v_src11 = vld1q_f32(S1 + x + 4);

            vst1q_f32(dst + x, vmlaq_f32(vmulq_f32(v_src00, v_b0), v_src10, v_b1));
            vst1q_f32(dst + x + 4, vmlaq_f32(vmulq_f32(v_src01, v_b0), v_src11, v_b1));
        }

        return x;
    }
};

typedef VResizeNoVec VResizeCubicVec_32s8u;

struct VResizeCubicVec_32f16u
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        ushort* dst = (ushort*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                         v_b1, vld1q_f32(S1 + x)),
                                                                         v_b2, vld1q_f32(S2 + x)),
                                                                         v_b3, vld1q_f32(S3 + x));
            float32x4_t v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x + 4)),
                                                                         v_b1, vld1q_f32(S1 + x + 4)),
                                                                         v_b2, vld1q_f32(S2 + x + 4)),
                                                                         v_b3, vld1q_f32(S3 + x + 4));

            vst1q_u16(dst + x, vcombine_u16(vqmovn_u32(cv_vrndq_u32_f32(v_dst0)),
                                            vqmovn_u32(cv_vrndq_u32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeCubicVec_32f16s
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        short* dst = (short*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                         v_b1, vld1q_f32(S1 + x)),
                                                                         v_b2, vld1q_f32(S2 + x)),
                                                                         v_b3, vld1q_f32(S3 + x));
            float32x4_t v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x + 4)),
                                                                         v_b1, vld1q_f32(S1 + x + 4)),
                                                                         v_b2, vld1q_f32(S2 + x + 4)),
                                                                         v_b3, vld1q_f32(S3 + x + 4));

            vst1q_s16(dst + x, vcombine_s16(vqmovn_s32(cv_vrndq_s32_f32(v_dst0)),
                                            vqmovn_s32(cv_vrndq_s32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeCubicVec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        float* dst = (float*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]);

        for( ; x <= width - 8; x += 8 )
        {
            vst1q_f32(dst + x, vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                       v_b1, vld1q_f32(S1 + x)),
                                                                       v_b2, vld1q_f32(S2 + x)),
                                                                       v_b3, vld1q_f32(S3 + x)));
            vst1q_f32(dst + x + 4, vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x + 4)),
                                                                          v_b1, vld1q_f32(S1 + x + 4)),
                                                                          v_b2, vld1q_f32(S2 + x + 4)),
                                                                          v_b3, vld1q_f32(S3 + x + 4)));
        }

        return x;
    }
};

struct VResizeLanczos4Vec_32f16u
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        ushort * dst = (ushort*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]),
                    v_b4 = vdupq_n_f32(beta[4]), v_b5 = vdupq_n_f32(beta[5]),
                    v_b6 = vdupq_n_f32(beta[6]), v_b7 = vdupq_n_f32(beta[7]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                         v_b1, vld1q_f32(S1 + x)),
                                                                         v_b2, vld1q_f32(S2 + x)),
                                                                         v_b3, vld1q_f32(S3 + x));
            float32x4_t v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b4, vld1q_f32(S4 + x)),
                                                                         v_b5, vld1q_f32(S5 + x)),
                                                                         v_b6, vld1q_f32(S6 + x)),
                                                                         v_b7, vld1q_f32(S7 + x));
            float32x4_t v_dst = vaddq_f32(v_dst0, v_dst1);

            v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x + 4)),
                                                             v_b1, vld1q_f32(S1 + x + 4)),
                                                             v_b2, vld1q_f32(S2 + x + 4)),
                                                             v_b3, vld1q_f32(S3 + x + 4));
            v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b4, vld1q_f32(S4 + x + 4)),
                                                             v_b5, vld1q_f32(S5 + x + 4)),
                                                             v_b6, vld1q_f32(S6 + x + 4)),
                                                             v_b7, vld1q_f32(S7 + x + 4));
            v_dst1 = vaddq_f32(v_dst0, v_dst1);

            vst1q_u16(dst + x, vcombine_u16(vqmovn_u32(cv_vrndq_u32_f32(v_dst)),
                                            vqmovn_u32(cv_vrndq_u32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeLanczos4Vec_32f16s
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        short * dst = (short*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]),
                    v_b4 = vdupq_n_f32(beta[4]), v_b5 = vdupq_n_f32(beta[5]),
                    v_b6 = vdupq_n_f32(beta[6]), v_b7 = vdupq_n_f32(beta[7]);

        for( ; x <= width - 8; x += 8 )
        {
            float32x4_t v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                         v_b1, vld1q_f32(S1 + x)),
                                                                         v_b2, vld1q_f32(S2 + x)),
                                                                         v_b3, vld1q_f32(S3 + x));
            float32x4_t v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b4, vld1q_f32(S4 + x)),
                                                                         v_b5, vld1q_f32(S5 + x)),
                                                                         v_b6, vld1q_f32(S6 + x)),
                                                                         v_b7, vld1q_f32(S7 + x));
            float32x4_t v_dst = vaddq_f32(v_dst0, v_dst1);

            v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x + 4)),
                                                             v_b1, vld1q_f32(S1 + x + 4)),
                                                             v_b2, vld1q_f32(S2 + x + 4)),
                                                             v_b3, vld1q_f32(S3 + x + 4));
            v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b4, vld1q_f32(S4 + x + 4)),
                                                             v_b5, vld1q_f32(S5 + x + 4)),
                                                             v_b6, vld1q_f32(S6 + x + 4)),
                                                             v_b7, vld1q_f32(S7 + x + 4));
            v_dst1 = vaddq_f32(v_dst0, v_dst1);

            vst1q_s16(dst + x, vcombine_s16(vqmovn_s32(cv_vrndq_s32_f32(v_dst)),
                                            vqmovn_s32(cv_vrndq_s32_f32(v_dst1))));
        }

        return x;
    }
};

struct VResizeLanczos4Vec_32f
{
    int operator()(const uchar** _src, uchar* _dst, const uchar* _beta, int width ) const
    {
        const float** src = (const float**)_src;
        const float* beta = (const float*)_beta;
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        float* dst = (float*)_dst;
        int x = 0;
        float32x4_t v_b0 = vdupq_n_f32(beta[0]), v_b1 = vdupq_n_f32(beta[1]),
                    v_b2 = vdupq_n_f32(beta[2]), v_b3 = vdupq_n_f32(beta[3]),
                    v_b4 = vdupq_n_f32(beta[4]), v_b5 = vdupq_n_f32(beta[5]),
                    v_b6 = vdupq_n_f32(beta[6]), v_b7 = vdupq_n_f32(beta[7]);

        for( ; x <= width - 4; x += 4 )
        {
            float32x4_t v_dst0 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b0, vld1q_f32(S0 + x)),
                                                                         v_b1, vld1q_f32(S1 + x)),
                                                                         v_b2, vld1q_f32(S2 + x)),
                                                                         v_b3, vld1q_f32(S3 + x));
            float32x4_t v_dst1 = vmlaq_f32(vmlaq_f32(vmlaq_f32(vmulq_f32(v_b4, vld1q_f32(S4 + x)),
                                                                         v_b5, vld1q_f32(S5 + x)),
                                                                         v_b6, vld1q_f32(S6 + x)),
                                                                         v_b7, vld1q_f32(S7 + x));
            vst1q_f32(dst + x, vaddq_f32(v_dst0, v_dst1));
        }

        return x;
    }
};

#else

typedef VResizeNoVec VResizeLinearVec_32s8u;
typedef VResizeNoVec VResizeLinearVec_32f16u;
typedef VResizeNoVec VResizeLinearVec_32f16s;
typedef VResizeNoVec VResizeLinearVec_32f;

typedef VResizeNoVec VResizeCubicVec_32s8u;
typedef VResizeNoVec VResizeCubicVec_32f16u;
typedef VResizeNoVec VResizeCubicVec_32f16s;
typedef VResizeNoVec VResizeCubicVec_32f;

typedef VResizeNoVec VResizeLanczos4Vec_32f16u;
typedef VResizeNoVec VResizeLanczos4Vec_32f16s;
typedef VResizeNoVec VResizeLanczos4Vec_32f;

#endif

typedef HResizeNoVec HResizeLinearVec_8u32s;
typedef HResizeNoVec HResizeLinearVec_16u32f;
typedef HResizeNoVec HResizeLinearVec_16s32f;
typedef HResizeNoVec HResizeLinearVec_32f;
typedef HResizeNoVec HResizeLinearVec_64f;


template<typename T, typename WT, typename AT, int ONE, class VecOp>
struct HResizeLinear
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        int dx, k;
        VecOp vecOp;

        int dx0 = vecOp((const uchar**)src, (uchar**)dst, count,
            xofs, (const uchar*)alpha, swidth, dwidth, cn, xmin, xmax );

        for( k = 0; k <= count - 2; k++ )
        {
            const T *S0 = src[k], *S1 = src[k+1];
            WT *D0 = dst[k], *D1 = dst[k+1];
            for( dx = dx0; dx < xmax; dx++ )
            {
                int sx = xofs[dx];
                WT a0 = alpha[dx*2], a1 = alpha[dx*2+1];
                WT t0 = S0[sx]*a0 + S0[sx + cn]*a1;
                WT t1 = S1[sx]*a0 + S1[sx + cn]*a1;
                D0[dx] = t0; D1[dx] = t1;
            }

            for( ; dx < dwidth; dx++ )
            {
                int sx = xofs[dx];
                D0[dx] = WT(S0[sx]*ONE); D1[dx] = WT(S1[sx]*ONE);
            }
        }

        for( ; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            for( dx = 0; dx < xmax; dx++ )
            {
                int sx = xofs[dx];
                D[dx] = S[sx]*alpha[dx*2] + S[sx+cn]*alpha[dx*2+1];
            }

            for( ; dx < dwidth; dx++ )
                D[dx] = WT(S[xofs[dx]]*ONE);
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeLinear
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        WT b0 = beta[0], b1 = beta[1];
        const WT *S0 = src[0], *S1 = src[1];
        CastOp castOp;
        VecOp vecOp;

        int x = vecOp((const uchar**)src, (uchar*)dst, (const uchar*)beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            WT t0, t1;
            t0 = S0[x]*b0 + S1[x]*b1;
            t1 = S0[x+1]*b0 + S1[x+1]*b1;
            dst[x] = castOp(t0); dst[x+1] = castOp(t1);
            t0 = S0[x+2]*b0 + S1[x+2]*b1;
            t1 = S0[x+3]*b0 + S1[x+3]*b1;
            dst[x+2] = castOp(t0); dst[x+3] = castOp(t1);
        }
        #endif
        for( ; x < width; x++ )
            dst[x] = castOp(S0[x]*b0 + S1[x]*b1);
    }
};

template<>
struct VResizeLinear<uchar, int, short, FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>, VResizeLinearVec_32s8u>
{
    typedef uchar value_type;
    typedef int buf_type;
    typedef short alpha_type;

    void operator()(const buf_type** src, value_type* dst, const alpha_type* beta, int width ) const
    {
        alpha_type b0 = beta[0], b1 = beta[1];
        const buf_type *S0 = src[0], *S1 = src[1];
        VResizeLinearVec_32s8u vecOp;

        int x = vecOp((const uchar**)src, (uchar*)dst, (const uchar*)beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            dst[x+0] = uchar(( ((b0 * (S0[x+0] >> 4)) >> 16) + ((b1 * (S1[x+0] >> 4)) >> 16) + 2)>>2);
            dst[x+1] = uchar(( ((b0 * (S0[x+1] >> 4)) >> 16) + ((b1 * (S1[x+1] >> 4)) >> 16) + 2)>>2);
            dst[x+2] = uchar(( ((b0 * (S0[x+2] >> 4)) >> 16) + ((b1 * (S1[x+2] >> 4)) >> 16) + 2)>>2);
            dst[x+3] = uchar(( ((b0 * (S0[x+3] >> 4)) >> 16) + ((b1 * (S1[x+3] >> 4)) >> 16) + 2)>>2);
        }
        #endif
        for( ; x < width; x++ )
            dst[x] = uchar(( ((b0 * (S0[x] >> 4)) >> 16) + ((b1 * (S1[x] >> 4)) >> 16) + 2)>>2);
    }
};


template<typename T, typename WT, typename AT>
struct HResizeCubic
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        for( int k = 0; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            int dx = 0, limit = xmin;
            for(;;)
            {
                for( ; dx < limit; dx++, alpha += 4 )
                {
                    int j, sx = xofs[dx] - cn;
                    WT v = 0;
                    for( j = 0; j < 4; j++ )
                    {
                        int sxj = sx + j*cn;
                        if( (unsigned)sxj >= (unsigned)swidth )
                        {
                            while( sxj < 0 )
                                sxj += cn;
                            while( sxj >= swidth )
                                sxj -= cn;
                        }
                        v += S[sxj]*alpha[j];
                    }
                    D[dx] = v;
                }
                if( limit == dwidth )
                    break;
                for( ; dx < xmax; dx++, alpha += 4 )
                {
                    int sx = xofs[dx];
                    D[dx] = S[sx-cn]*alpha[0] + S[sx]*alpha[1] +
                        S[sx+cn]*alpha[2] + S[sx+cn*2]*alpha[3];
                }
                limit = dwidth;
            }
            alpha -= dwidth*4;
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeCubic
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        WT b0 = beta[0], b1 = beta[1], b2 = beta[2], b3 = beta[3];
        const WT *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        CastOp castOp;
        VecOp vecOp;

        int x = vecOp((const uchar**)src, (uchar*)dst, (const uchar*)beta, width);
        for( ; x < width; x++ )
            dst[x] = castOp(S0[x]*b0 + S1[x]*b1 + S2[x]*b2 + S3[x]*b3);
    }
};


template<typename T, typename WT, typename AT>
struct HResizeLanczos4
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        for( int k = 0; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            int dx = 0, limit = xmin;
            for(;;)
            {
                for( ; dx < limit; dx++, alpha += 8 )
                {
                    int j, sx = xofs[dx] - cn*3;
                    WT v = 0;
                    for( j = 0; j < 8; j++ )
                    {
                        int sxj = sx + j*cn;
                        if( (unsigned)sxj >= (unsigned)swidth )
                        {
                            while( sxj < 0 )
                                sxj += cn;
                            while( sxj >= swidth )
                                sxj -= cn;
                        }
                        v += S[sxj]*alpha[j];
                    }
                    D[dx] = v;
                }
                if( limit == dwidth )
                    break;
                for( ; dx < xmax; dx++, alpha += 8 )
                {
                    int sx = xofs[dx];
                    D[dx] = S[sx-cn*3]*alpha[0] + S[sx-cn*2]*alpha[1] +
                        S[sx-cn]*alpha[2] + S[sx]*alpha[3] +
                        S[sx+cn]*alpha[4] + S[sx+cn*2]*alpha[5] +
                        S[sx+cn*3]*alpha[6] + S[sx+cn*4]*alpha[7];
                }
                limit = dwidth;
            }
            alpha -= dwidth*8;
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeLanczos4
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        CastOp castOp;
        VecOp vecOp;
        int x = vecOp((const uchar**)src, (uchar*)dst, (const uchar*)beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            WT b = beta[0];
            const WT* S = src[0];
            WT s0 = S[x]*b, s1 = S[x+1]*b, s2 = S[x+2]*b, s3 = S[x+3]*b;

            for( int k = 1; k < 8; k++ )
            {
                b = beta[k]; S = src[k];
                s0 += S[x]*b; s1 += S[x+1]*b;
                s2 += S[x+2]*b; s3 += S[x+3]*b;
            }

            dst[x] = castOp(s0); dst[x+1] = castOp(s1);
            dst[x+2] = castOp(s2); dst[x+3] = castOp(s3);
        }
        #endif
        for( ; x < width; x++ )
        {
            dst[x] = castOp(src[0][x]*beta[0] + src[1][x]*beta[1] +
                src[2][x]*beta[2] + src[3][x]*beta[3] + src[4][x]*beta[4] +
                src[5][x]*beta[5] + src[6][x]*beta[6] + src[7][x]*beta[7]);
        }
    }
};


static inline int clip(int x, int a, int b)
{
    return x >= a ? (x < b ? x : b-1) : a;
}

static const int MAX_ESIZE=16;

template <typename HResize, typename VResize>
class resizeGeneric_Invoker :
    public ParallelLoopBody
{
public:
    typedef typename HResize::value_type T;
    typedef typename HResize::buf_type WT;
    typedef typename HResize::alpha_type AT;

    resizeGeneric_Invoker(const Mat& _src, Mat &_dst, const int *_xofs, const int *_yofs,
        const AT* _alpha, const AT* __beta, const Size& _ssize, const Size &_dsize,
        int _ksize, int _xmin, int _xmax) :
        ParallelLoopBody(), src(_src), dst(_dst), xofs(_xofs), yofs(_yofs),
        alpha(_alpha), _beta(__beta), ssize(_ssize), dsize(_dsize),
        ksize(_ksize), xmin(_xmin), xmax(_xmax)
    {
        CV_Assert(ksize <= MAX_ESIZE);
    }

    virtual void operator() (const Range& range) const
    {
        int dy, cn = src.channels();
        HResize hresize;
        VResize vresize;

        int bufstep = (int)alignSize(dsize.width, 16);
        AutoBuffer<WT> _buffer(bufstep*ksize);
        const T* srows[MAX_ESIZE]={0};
        WT* rows[MAX_ESIZE]={0};
        int prev_sy[MAX_ESIZE];

        for(int k = 0; k < ksize; k++ )
        {
            prev_sy[k] = -1;
            rows[k] = (WT*)_buffer + bufstep*k;
        }

        const AT* beta = _beta + ksize * range.start;

        for( dy = range.start; dy < range.end; dy++, beta += ksize )
        {
            int sy0 = yofs[dy], k0=ksize, k1=0, ksize2 = ksize/2;

            for(int k = 0; k < ksize; k++ )
            {
                int sy = clip(sy0 - ksize2 + 1 + k, 0, ssize.height);
                for( k1 = std::max(k1, k); k1 < ksize; k1++ )
                {
                    if( k1 < MAX_ESIZE && sy == prev_sy[k1] ) // if the sy-th row has been computed already, reuse it.
                    {
                        if( k1 > k )
                            memcpy( rows[k], rows[k1], bufstep*sizeof(rows[0][0]) );
                        break;
                    }
                }
                if( k1 == ksize )
                    k0 = std::min(k0, k); // remember the first row that needs to be computed
                srows[k] = src.template ptr<T>(sy);
                prev_sy[k] = sy;
            }

            if( k0 < ksize )
                hresize( (const T**)(srows + k0), (WT**)(rows + k0), ksize - k0, xofs, (const AT*)(alpha),
                        ssize.width, dsize.width, cn, xmin, xmax );
            vresize( (const WT**)rows, (T*)(dst.data + dst.step*dy), beta, dsize.width );
        }
    }

private:
    Mat src;
    Mat dst;
    const int* xofs, *yofs;
    const AT* alpha, *_beta;
    Size ssize, dsize;
    const int ksize, xmin, xmax;

    resizeGeneric_Invoker& operator = (const resizeGeneric_Invoker&);
};

template<class HResize, class VResize>
static void resizeGeneric_( const Mat& src, Mat& dst,
                            const int* xofs, const void* _alpha,
                            const int* yofs, const void* _beta,
                            int xmin, int xmax, int ksize )
{
    typedef typename HResize::alpha_type AT;

    const AT* beta = (const AT*)_beta;
    Size ssize = src.size(), dsize = dst.size();
    int cn = src.channels();
    ssize.width *= cn;
    dsize.width *= cn;
    xmin *= cn;
    xmax *= cn;
    // image resize is a separable operation. In case of not too strong

    Range range(0, dsize.height);
    resizeGeneric_Invoker<HResize, VResize> invoker(src, dst, xofs, yofs, (const AT*)_alpha, beta,
        ssize, dsize, ksize, xmin, xmax);
    parallel_for_(range, invoker, dst.total()/(double)(1<<16));
}

template <typename T, typename WT>
struct ResizeAreaFastNoVec
{
    ResizeAreaFastNoVec(int, int) { }
    ResizeAreaFastNoVec(int, int, int, int) { }
    int operator() (const T*, T*, int) const
    { return 0; }
};

#if CV_NEON

class ResizeAreaFastVec_SIMD_8u
{
public:
    ResizeAreaFastVec_SIMD_8u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const uchar* S, uchar* D, int w) const
    {
        int dx = 0;
        const uchar* S0 = S, * S1 = S0 + step;

        uint16x8_t v_2 = vdupq_n_u16(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 16; dx += 16, S0 += 32, S1 += 32, D += 16)
            {
                uint8x16x2_t v_row0 = vld2q_u8(S0), v_row1 = vld2q_u8(S1);

                uint16x8_t v_dst0 = vaddl_u8(vget_low_u8(v_row0.val[0]), vget_low_u8(v_row0.val[1]));
                v_dst0 = vaddq_u16(v_dst0, vaddl_u8(vget_low_u8(v_row1.val[0]), vget_low_u8(v_row1.val[1])));
                v_dst0 = vshrq_n_u16(vaddq_u16(v_dst0, v_2), 2);

                uint16x8_t v_dst1 = vaddl_u8(vget_high_u8(v_row0.val[0]), vget_high_u8(v_row0.val[1]));
                v_dst1 = vaddq_u16(v_dst1, vaddl_u8(vget_high_u8(v_row1.val[0]), vget_high_u8(v_row1.val[1])));
                v_dst1 = vshrq_n_u16(vaddq_u16(v_dst1, v_2), 2);

                vst1q_u8(D, vcombine_u8(vmovn_u16(v_dst0), vmovn_u16(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                uint8x16_t v_row0 = vld1q_u8(S0), v_row1 = vld1q_u8(S1);

                uint16x8_t v_row00 = vmovl_u8(vget_low_u8(v_row0));
                uint16x8_t v_row01 = vmovl_u8(vget_high_u8(v_row0));
                uint16x8_t v_row10 = vmovl_u8(vget_low_u8(v_row1));
                uint16x8_t v_row11 = vmovl_u8(vget_high_u8(v_row1));

                uint16x4_t v_p0 = vadd_u16(vadd_u16(vget_low_u16(v_row00), vget_high_u16(v_row00)),
                                           vadd_u16(vget_low_u16(v_row10), vget_high_u16(v_row10)));
                uint16x4_t v_p1 = vadd_u16(vadd_u16(vget_low_u16(v_row01), vget_high_u16(v_row01)),
                                           vadd_u16(vget_low_u16(v_row11), vget_high_u16(v_row11)));
                uint16x8_t v_dst = vshrq_n_u16(vaddq_u16(vcombine_u16(v_p0, v_p1), v_2), 2);

                vst1_u8(D, vmovn_u16(v_dst));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

class ResizeAreaFastVec_SIMD_16u
{
public:
    ResizeAreaFastVec_SIMD_16u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const ushort * S, ushort * D, int w) const
    {
        int dx = 0;
        const ushort * S0 = S, * S1 = (const ushort *)((const uchar *)(S0) + step);

        uint32x4_t v_2 = vdupq_n_u32(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                uint16x8x2_t v_row0 = vld2q_u16(S0), v_row1 = vld2q_u16(S1);

                uint32x4_t v_dst0 = vaddl_u16(vget_low_u16(v_row0.val[0]), vget_low_u16(v_row0.val[1]));
                v_dst0 = vaddq_u32(v_dst0, vaddl_u16(vget_low_u16(v_row1.val[0]), vget_low_u16(v_row1.val[1])));
                v_dst0 = vshrq_n_u32(vaddq_u32(v_dst0, v_2), 2);

                uint32x4_t v_dst1 = vaddl_u16(vget_high_u16(v_row0.val[0]), vget_high_u16(v_row0.val[1]));
                v_dst1 = vaddq_u32(v_dst1, vaddl_u16(vget_high_u16(v_row1.val[0]), vget_high_u16(v_row1.val[1])));
                v_dst1 = vshrq_n_u32(vaddq_u32(v_dst1, v_2), 2);

                vst1q_u16(D, vcombine_u16(vmovn_u32(v_dst0), vmovn_u32(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                uint16x8_t v_row0 = vld1q_u16(S0), v_row1 = vld1q_u16(S1);
                uint32x4_t v_dst = vaddq_u32(vaddl_u16(vget_low_u16(v_row0), vget_high_u16(v_row0)),
                                             vaddl_u16(vget_low_u16(v_row1), vget_high_u16(v_row1)));
                vst1_u16(D, vmovn_u32(vshrq_n_u32(vaddq_u32(v_dst, v_2), 2)));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

class ResizeAreaFastVec_SIMD_16s
{
public:
    ResizeAreaFastVec_SIMD_16s(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const short * S, short * D, int w) const
    {
        int dx = 0;
        const short * S0 = S, * S1 = (const short *)((const uchar *)(S0) + step);

        int32x4_t v_2 = vdupq_n_s32(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                int16x8x2_t v_row0 = vld2q_s16(S0), v_row1 = vld2q_s16(S1);

                int32x4_t v_dst0 = vaddl_s16(vget_low_s16(v_row0.val[0]), vget_low_s16(v_row0.val[1]));
                v_dst0 = vaddq_s32(v_dst0, vaddl_s16(vget_low_s16(v_row1.val[0]), vget_low_s16(v_row1.val[1])));
                v_dst0 = vshrq_n_s32(vaddq_s32(v_dst0, v_2), 2);

                int32x4_t v_dst1 = vaddl_s16(vget_high_s16(v_row0.val[0]), vget_high_s16(v_row0.val[1]));
                v_dst1 = vaddq_s32(v_dst1, vaddl_s16(vget_high_s16(v_row1.val[0]), vget_high_s16(v_row1.val[1])));
                v_dst1 = vshrq_n_s32(vaddq_s32(v_dst1, v_2), 2);

                vst1q_s16(D, vcombine_s16(vmovn_s32(v_dst0), vmovn_s32(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                int16x8_t v_row0 = vld1q_s16(S0), v_row1 = vld1q_s16(S1);
                int32x4_t v_dst = vaddq_s32(vaddl_s16(vget_low_s16(v_row0), vget_high_s16(v_row0)),
                                            vaddl_s16(vget_low_s16(v_row1), vget_high_s16(v_row1)));
                vst1_s16(D, vmovn_s32(vshrq_n_s32(vaddq_s32(v_dst, v_2), 2)));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

struct ResizeAreaFastVec_SIMD_32f
{
    ResizeAreaFastVec_SIMD_32f(int _scale_x, int _scale_y, int _cn, int _step) :
        cn(_cn), step(_step)
    {
        fast_mode = _scale_x == 2 && _scale_y == 2 && (cn == 1 || cn == 4);
    }

    int operator() (const float * S, float * D, int w) const
    {
        if (!fast_mode)
            return 0;

        const float * S0 = S, * S1 = (const float *)((const uchar *)(S0) + step);
        int dx = 0;

        float32x4_t v_025 = vdupq_n_f32(0.25f);

        if (cn == 1)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                float32x4x2_t v_row0 = vld2q_f32(S0), v_row1 = vld2q_f32(S1);

                float32x4_t v_dst0 = vaddq_f32(v_row0.val[0], v_row0.val[1]);
                float32x4_t v_dst1 = vaddq_f32(v_row1.val[0], v_row1.val[1]);

                vst1q_f32(D, vmulq_f32(vaddq_f32(v_dst0, v_dst1), v_025));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                float32x4_t v_dst0 = vaddq_f32(vld1q_f32(S0), vld1q_f32(S0 + 4));
                float32x4_t v_dst1 = vaddq_f32(vld1q_f32(S1), vld1q_f32(S1 + 4));

                vst1q_f32(D, vmulq_f32(vaddq_f32(v_dst0, v_dst1), v_025));
            }
        }

        return dx;
    }

private:
    int cn;
    bool fast_mode;
    int step;
};

#elif CV_SSE2

class ResizeAreaFastVec_SIMD_8u
{
public:
    ResizeAreaFastVec_SIMD_8u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
        use_simd = checkHardwareSupport(CV_CPU_SSE2);
    }

    int operator() (const uchar* S, uchar* D, int w) const
    {
        if (!use_simd)
            return 0;

        int dx = 0;
        const uchar* S0 = S;
        const uchar* S1 = S0 + step;
        __m128i zero = _mm_setzero_si128();
        __m128i delta2 = _mm_set1_epi16(2);

        if (cn == 1)
        {
            __m128i masklow = _mm_set1_epi16(0x00ff);
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i s0 = _mm_add_epi16(_mm_srli_epi16(r0, 8), _mm_and_si128(r0, masklow));
                __m128i s1 = _mm_add_epi16(_mm_srli_epi16(r1, 8), _mm_and_si128(r1, masklow));
                s0 = _mm_add_epi16(_mm_add_epi16(s0, s1), delta2);
                s0 = _mm_packus_epi16(_mm_srli_epi16(s0, 2), zero);

                _mm_storel_epi64((__m128i*)D, s0);
            }
        }
        else if (cn == 3)
            for ( ; dx <= w - 11; dx += 6, S0 += 12, S1 += 12, D += 6)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_16l = _mm_unpacklo_epi8(r0, zero);
                __m128i r0_16h = _mm_unpacklo_epi8(_mm_srli_si128(r0, 6), zero);
                __m128i r1_16l = _mm_unpacklo_epi8(r1, zero);
                __m128i r1_16h = _mm_unpacklo_epi8(_mm_srli_si128(r1, 6), zero);

                __m128i s0 = _mm_add_epi16(r0_16l, _mm_srli_si128(r0_16l, 6));
                __m128i s1 = _mm_add_epi16(r1_16l, _mm_srli_si128(r1_16l, 6));
                s0 = _mm_add_epi16(s1, _mm_add_epi16(s0, delta2));
                s0 = _mm_packus_epi16(_mm_srli_epi16(s0, 2), zero);
                _mm_storel_epi64((__m128i*)D, s0);

                s0 = _mm_add_epi16(r0_16h, _mm_srli_si128(r0_16h, 6));
                s1 = _mm_add_epi16(r1_16h, _mm_srli_si128(r1_16h, 6));
                s0 = _mm_add_epi16(s1, _mm_add_epi16(s0, delta2));
                s0 = _mm_packus_epi16(_mm_srli_epi16(s0, 2), zero);
                _mm_storel_epi64((__m128i*)(D+3), s0);
            }
        else
        {
            CV_Assert(cn == 4);
            int v[] = { 0, 0, -1, -1 };
            __m128i mask = _mm_loadu_si128((const __m128i*)v);

            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_16l = _mm_unpacklo_epi8(r0, zero);
                __m128i r0_16h = _mm_unpackhi_epi8(r0, zero);
                __m128i r1_16l = _mm_unpacklo_epi8(r1, zero);
                __m128i r1_16h = _mm_unpackhi_epi8(r1, zero);

                __m128i s0 = _mm_add_epi16(r0_16l, _mm_srli_si128(r0_16l, 8));
                __m128i s1 = _mm_add_epi16(r1_16l, _mm_srli_si128(r1_16l, 8));
                s0 = _mm_add_epi16(s1, _mm_add_epi16(s0, delta2));
                __m128i res0 = _mm_srli_epi16(s0, 2);

                s0 = _mm_add_epi16(r0_16h, _mm_srli_si128(r0_16h, 8));
                s1 = _mm_add_epi16(r1_16h, _mm_srli_si128(r1_16h, 8));
                s0 = _mm_add_epi16(s1, _mm_add_epi16(s0, delta2));
                __m128i res1 = _mm_srli_epi16(s0, 2);
                s0 = _mm_packus_epi16(_mm_or_si128(_mm_andnot_si128(mask, res0),
                                                   _mm_and_si128(mask, _mm_slli_si128(res1, 8))), zero);
                _mm_storel_epi64((__m128i*)(D), s0);
            }
        }

        return dx;
    }

private:
    int cn;
    bool use_simd;
    int step;
};

class ResizeAreaFastVec_SIMD_16u
{
public:
    ResizeAreaFastVec_SIMD_16u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
        use_simd = checkHardwareSupport(CV_CPU_SSE2);
    }

    int operator() (const ushort* S, ushort* D, int w) const
    {
        if (!use_simd)
            return 0;

        int dx = 0;
        const ushort* S0 = (const ushort*)S;
        const ushort* S1 = (const ushort*)((const uchar*)(S) + step);
        __m128i masklow = _mm_set1_epi32(0x0000ffff);
        __m128i zero = _mm_setzero_si128();
        __m128i delta2 = _mm_set1_epi32(2);

#define _mm_packus_epi32(a, zero) _mm_packs_epi32(_mm_srai_epi32(_mm_slli_epi32(a, 16), 16), zero)

        if (cn == 1)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i s0 = _mm_add_epi32(_mm_srli_epi32(r0, 16), _mm_and_si128(r0, masklow));
                __m128i s1 = _mm_add_epi32(_mm_srli_epi32(r1, 16), _mm_and_si128(r1, masklow));
                s0 = _mm_add_epi32(_mm_add_epi32(s0, s1), delta2);
                s0 = _mm_srli_epi32(s0, 2);
                s0 = _mm_packus_epi32(s0, zero);

                _mm_storel_epi64((__m128i*)D, s0);
            }
        }
        else if (cn == 3)
            for ( ; dx <= w - 4; dx += 3, S0 += 6, S1 += 6, D += 3)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_16l = _mm_unpacklo_epi16(r0, zero);
                __m128i r0_16h = _mm_unpacklo_epi16(_mm_srli_si128(r0, 6), zero);
                __m128i r1_16l = _mm_unpacklo_epi16(r1, zero);
                __m128i r1_16h = _mm_unpacklo_epi16(_mm_srli_si128(r1, 6), zero);

                __m128i s0 = _mm_add_epi32(r0_16l, r0_16h);
                __m128i s1 = _mm_add_epi32(r1_16l, r1_16h);
                s0 = _mm_add_epi32(delta2, _mm_add_epi32(s0, s1));
                s0 = _mm_packus_epi32(_mm_srli_epi32(s0, 2), zero);
                _mm_storel_epi64((__m128i*)D, s0);
            }
        else
        {
            CV_Assert(cn == 4);
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_32l = _mm_unpacklo_epi16(r0, zero);
                __m128i r0_32h = _mm_unpackhi_epi16(r0, zero);
                __m128i r1_32l = _mm_unpacklo_epi16(r1, zero);
                __m128i r1_32h = _mm_unpackhi_epi16(r1, zero);

                __m128i s0 = _mm_add_epi32(r0_32l, r0_32h);
                __m128i s1 = _mm_add_epi32(r1_32l, r1_32h);
                s0 = _mm_add_epi32(s1, _mm_add_epi32(s0, delta2));
                s0 = _mm_packus_epi32(_mm_srli_epi32(s0, 2), zero);
                _mm_storel_epi64((__m128i*)D, s0);
            }
        }

#undef _mm_packus_epi32

        return dx;
    }

private:
    int cn;
    int step;
    bool use_simd;
};

class ResizeAreaFastVec_SIMD_16s
{
public:
    ResizeAreaFastVec_SIMD_16s(int _cn, int _step) :
        cn(_cn), step(_step)
    {
        use_simd = checkHardwareSupport(CV_CPU_SSE2);
    }

    int operator() (const short* S, short* D, int w) const
    {
        if (!use_simd)
            return 0;

        int dx = 0;
        const short* S0 = (const short*)S;
        const short* S1 = (const short*)((const uchar*)(S) + step);
        __m128i masklow = _mm_set1_epi32(0x0000ffff);
        __m128i zero = _mm_setzero_si128();
        __m128i delta2 = _mm_set1_epi32(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i s0 = _mm_add_epi32(_mm_srai_epi32(r0, 16),
                    _mm_srai_epi32(_mm_slli_epi32(_mm_and_si128(r0, masklow), 16), 16));
                __m128i s1 = _mm_add_epi32(_mm_srai_epi32(r1, 16),
                    _mm_srai_epi32(_mm_slli_epi32(_mm_and_si128(r1, masklow), 16), 16));
                s0 = _mm_add_epi32(_mm_add_epi32(s0, s1), delta2);
                s0 = _mm_srai_epi32(s0, 2);
                s0 = _mm_packs_epi32(s0, zero);

                _mm_storel_epi64((__m128i*)D, s0);
            }
        }
        else if (cn == 3)
            for ( ; dx <= w - 4; dx += 3, S0 += 6, S1 += 6, D += 3)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_16l = _mm_srai_epi32(_mm_unpacklo_epi16(zero, r0), 16);
                __m128i r0_16h = _mm_srai_epi32(_mm_unpacklo_epi16(zero, _mm_srli_si128(r0, 6)), 16);
                __m128i r1_16l = _mm_srai_epi32(_mm_unpacklo_epi16(zero, r1), 16);
                __m128i r1_16h = _mm_srai_epi32(_mm_unpacklo_epi16(zero, _mm_srli_si128(r1, 6)), 16);

                __m128i s0 = _mm_add_epi32(r0_16l, r0_16h);
                __m128i s1 = _mm_add_epi32(r1_16l, r1_16h);
                s0 = _mm_add_epi32(delta2, _mm_add_epi32(s0, s1));
                s0 = _mm_packs_epi32(_mm_srai_epi32(s0, 2), zero);
                _mm_storel_epi64((__m128i*)D, s0);
            }
        else
        {
            CV_Assert(cn == 4);
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128i r0 = _mm_loadu_si128((const __m128i*)S0);
                __m128i r1 = _mm_loadu_si128((const __m128i*)S1);

                __m128i r0_32l = _mm_srai_epi32(_mm_unpacklo_epi16(zero, r0), 16);
                __m128i r0_32h = _mm_srai_epi32(_mm_unpackhi_epi16(zero, r0), 16);
                __m128i r1_32l = _mm_srai_epi32(_mm_unpacklo_epi16(zero, r1), 16);
                __m128i r1_32h = _mm_srai_epi32(_mm_unpackhi_epi16(zero, r1), 16);

                __m128i s0 = _mm_add_epi32(r0_32l, r0_32h);
                __m128i s1 = _mm_add_epi32(r1_32l, r1_32h);
                s0 = _mm_add_epi32(s1, _mm_add_epi32(s0, delta2));
                s0 = _mm_packs_epi32(_mm_srai_epi32(s0, 2), zero);
                _mm_storel_epi64((__m128i*)D, s0);
            }
        }

        return dx;
    }

private:
    int cn;
    int step;
    bool use_simd;
};

struct ResizeAreaFastVec_SIMD_32f
{
    ResizeAreaFastVec_SIMD_32f(int _scale_x, int _scale_y, int _cn, int _step) :
        cn(_cn), step(_step)
    {
        fast_mode = _scale_x == 2 && _scale_y == 2 && (cn == 1 || cn == 4);
        fast_mode = fast_mode && checkHardwareSupport(CV_CPU_SSE2);
    }

    int operator() (const float * S, float * D, int w) const
    {
        if (!fast_mode)
            return 0;

        const float * S0 = S, * S1 = (const float *)((const uchar *)(S0) + step);
        int dx = 0;

        __m128 v_025 = _mm_set1_ps(0.25f);

        if (cn == 1)
        {
            const int shuffle_lo = _MM_SHUFFLE(2, 0, 2, 0), shuffle_hi = _MM_SHUFFLE(3, 1, 3, 1);
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128 v_row00 = _mm_loadu_ps(S0), v_row01 = _mm_loadu_ps(S0 + 4),
                       v_row10 = _mm_loadu_ps(S1), v_row11 = _mm_loadu_ps(S1 + 4);

                __m128 v_dst0 = _mm_add_ps(_mm_shuffle_ps(v_row00, v_row01, shuffle_lo),
                                           _mm_shuffle_ps(v_row00, v_row01, shuffle_hi));
                __m128 v_dst1 = _mm_add_ps(_mm_shuffle_ps(v_row10, v_row11, shuffle_lo),
                                           _mm_shuffle_ps(v_row10, v_row11, shuffle_hi));

                _mm_storeu_ps(D, _mm_mul_ps(_mm_add_ps(v_dst0, v_dst1), v_025));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                __m128 v_dst0 = _mm_add_ps(_mm_loadu_ps(S0), _mm_loadu_ps(S0 + 4));
                __m128 v_dst1 = _mm_add_ps(_mm_loadu_ps(S1), _mm_loadu_ps(S1 + 4));

                _mm_storeu_ps(D, _mm_mul_ps(_mm_add_ps(v_dst0, v_dst1), v_025));
            }
        }

        return dx;
    }

private:
    int cn;
    bool fast_mode;
    int step;
};

#else

typedef ResizeAreaFastNoVec<uchar, uchar> ResizeAreaFastVec_SIMD_8u;
typedef ResizeAreaFastNoVec<ushort, ushort> ResizeAreaFastVec_SIMD_16u;
typedef ResizeAreaFastNoVec<short, short> ResizeAreaFastVec_SIMD_16s;
typedef ResizeAreaFastNoVec<float, float> ResizeAreaFastVec_SIMD_32f;

#endif

template<typename T, typename SIMDVecOp>
struct ResizeAreaFastVec
{
    ResizeAreaFastVec(int _scale_x, int _scale_y, int _cn, int _step) :
        scale_x(_scale_x), scale_y(_scale_y), cn(_cn), step(_step), vecOp(_cn, _step)
    {
        fast_mode = scale_x == 2 && scale_y == 2 && (cn == 1 || cn == 3 || cn == 4);
    }

    int operator() (const T* S, T* D, int w) const
    {
        if (!fast_mode)
            return 0;

        const T* nextS = (const T*)((const uchar*)S + step);
        int dx = vecOp(S, D, w);

        if (cn == 1)
            for( ; dx < w; ++dx )
            {
                int index = dx*2;
                D[dx] = (T)((S[index] + S[index+1] + nextS[index] + nextS[index+1] + 2) >> 2);
            }
        else if (cn == 3)
            for( ; dx < w; dx += 3 )
            {
                int index = dx*2;
                D[dx] = (T)((S[index] + S[index+3] + nextS[index] + nextS[index+3] + 2) >> 2);
                D[dx+1] = (T)((S[index+1] + S[index+4] + nextS[index+1] + nextS[index+4] + 2) >> 2);
                D[dx+2] = (T)((S[index+2] + S[index+5] + nextS[index+2] + nextS[index+5] + 2) >> 2);
            }
        else
            {
                CV_Assert(cn == 4);
                for( ; dx < w; dx += 4 )
                {
                    int index = dx*2;
                    D[dx] = (T)((S[index] + S[index+4] + nextS[index] + nextS[index+4] + 2) >> 2);
                    D[dx+1] = (T)((S[index+1] + S[index+5] + nextS[index+1] + nextS[index+5] + 2) >> 2);
                    D[dx+2] = (T)((S[index+2] + S[index+6] + nextS[index+2] + nextS[index+6] + 2) >> 2);
                    D[dx+3] = (T)((S[index+3] + S[index+7] + nextS[index+3] + nextS[index+7] + 2) >> 2);
                }
            }

        return dx;
    }

private:
    int scale_x, scale_y;
    int cn;
    bool fast_mode;
    int step;
    SIMDVecOp vecOp;
};

template <typename T, typename WT, typename VecOp>
class resizeAreaFast_Invoker :
    public ParallelLoopBody
{
public:
    resizeAreaFast_Invoker(const Mat &_src, Mat &_dst,
        int _scale_x, int _scale_y, const int* _ofs, const int* _xofs) :
        ParallelLoopBody(), src(_src), dst(_dst), scale_x(_scale_x),
        scale_y(_scale_y), ofs(_ofs), xofs(_xofs)
    {
    }

    virtual void operator() (const Range& range) const
    {
        Size ssize = src.size(), dsize = dst.size();
        int cn = src.channels();
        int area = scale_x*scale_y;
        float scale = 1.f/(area);
        int dwidth1 = (ssize.width/scale_x)*cn;
        dsize.width *= cn;
        ssize.width *= cn;
        int dy, dx, k = 0;

        VecOp vop(scale_x, scale_y, src.channels(), (int)src.step/*, area_ofs*/);

        for( dy = range.start; dy < range.end; dy++ )
        {
            T* D = (T*)(dst.data + dst.step*dy);
            int sy0 = dy*scale_y;
            int w = sy0 + scale_y <= ssize.height ? dwidth1 : 0;

            if( sy0 >= ssize.height )
            {
                for( dx = 0; dx < dsize.width; dx++ )
                    D[dx] = 0;
                continue;
            }

            dx = vop(src.template ptr<T>(sy0), D, w);
            for( ; dx < w; dx++ )
            {
                const T* S = src.template ptr<T>(sy0) + xofs[dx];
                WT sum = 0;
                k = 0;
                #if CV_ENABLE_UNROLLED
                for( ; k <= area - 4; k += 4 )
                    sum += S[ofs[k]] + S[ofs[k+1]] + S[ofs[k+2]] + S[ofs[k+3]];
                #endif
                for( ; k < area; k++ )
                    sum += S[ofs[k]];

                D[dx] = saturate_cast<T>(sum * scale);
            }

            for( ; dx < dsize.width; dx++ )
            {
                WT sum = 0;
                int count = 0, sx0 = xofs[dx];
                if( sx0 >= ssize.width )
                    D[dx] = 0;

                for( int sy = 0; sy < scale_y; sy++ )
                {
                    if( sy0 + sy >= ssize.height )
                        break;
                    const T* S = src.template ptr<T>(sy0 + sy) + sx0;
                    for( int sx = 0; sx < scale_x*cn; sx += cn )
                    {
                        if( sx0 + sx >= ssize.width )
                            break;
                        sum += S[sx];
                        count++;
                    }
                }

                D[dx] = saturate_cast<T>((float)sum/count);
            }
        }
    }

private:
    Mat src;
    Mat dst;
    int scale_x, scale_y;
    const int *ofs, *xofs;
};

template<typename T, typename WT, typename VecOp>
static void resizeAreaFast_( const Mat& src, Mat& dst, const int* ofs, const int* xofs,
                             int scale_x, int scale_y )
{
    Range range(0, dst.rows);
    resizeAreaFast_Invoker<T, WT, VecOp> invoker(src, dst, scale_x,
        scale_y, ofs, xofs);
    parallel_for_(range, invoker, dst.total()/(double)(1<<16));
}

struct DecimateAlpha
{
    int si, di;
    float alpha;
};


template<typename T, typename WT> class ResizeArea_Invoker :
    public ParallelLoopBody
{
public:
    ResizeArea_Invoker( const Mat& _src, Mat& _dst,
                        const DecimateAlpha* _xtab, int _xtab_size,
                        const DecimateAlpha* _ytab, int _ytab_size,
                        const int* _tabofs )
    {
        src = &_src;
        dst = &_dst;
        xtab0 = _xtab;
        xtab_size0 = _xtab_size;
        ytab = _ytab;
        ytab_size = _ytab_size;
        tabofs = _tabofs;
    }

    virtual void operator() (const Range& range) const
    {
        Size dsize = dst->size();
        int cn = dst->channels();
        dsize.width *= cn;
        AutoBuffer<WT> _buffer(dsize.width*2);
        const DecimateAlpha* xtab = xtab0;
        int xtab_size = xtab_size0;
        WT *buf = _buffer, *sum = buf + dsize.width;
        int j_start = tabofs[range.start], j_end = tabofs[range.end], j, k, dx, prev_dy = ytab[j_start].di;

        for( dx = 0; dx < dsize.width; dx++ )
            sum[dx] = (WT)0;

        for( j = j_start; j < j_end; j++ )
        {
            WT beta = ytab[j].alpha;
            int dy = ytab[j].di;
            int sy = ytab[j].si;

            {
                const T* S = src->template ptr<T>(sy);
                for( dx = 0; dx < dsize.width; dx++ )
                    buf[dx] = (WT)0;

                if( cn == 1 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        buf[dxn] += S[xtab[k].si]*alpha;
                    }
                else if( cn == 2 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1;
                    }
                else if( cn == 3 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        WT t2 = buf[dxn+2] + S[sxn+2]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1; buf[dxn+2] = t2;
                    }
                else if( cn == 4 )
                {
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1;
                        t0 = buf[dxn+2] + S[sxn+2]*alpha;
                        t1 = buf[dxn+3] + S[sxn+3]*alpha;
                        buf[dxn+2] = t0; buf[dxn+3] = t1;
                    }
                }
                else
                {
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        for( int c = 0; c < cn; c++ )
                            buf[dxn + c] += S[sxn + c]*alpha;
                    }
                }
            }

            if( dy != prev_dy )
            {
                T* D = dst->template ptr<T>(prev_dy);

                for( dx = 0; dx < dsize.width; dx++ )
                {
                    D[dx] = saturate_cast<T>(sum[dx]);
                    sum[dx] = beta*buf[dx];
                }
                prev_dy = dy;
            }
            else
            {
                for( dx = 0; dx < dsize.width; dx++ )
                    sum[dx] += beta*buf[dx];
            }
        }

        {
        T* D = dst->template ptr<T>(prev_dy);
        for( dx = 0; dx < dsize.width; dx++ )
            D[dx] = saturate_cast<T>(sum[dx]);
        }
    }

private:
    const Mat* src;
    Mat* dst;
    const DecimateAlpha* xtab0;
    const DecimateAlpha* ytab;
    int xtab_size0, ytab_size;
    const int* tabofs;
};


template <typename T, typename WT>
static void resizeArea_( const Mat& src, Mat& dst,
                         const DecimateAlpha* xtab, int xtab_size,
                         const DecimateAlpha* ytab, int ytab_size,
                         const int* tabofs )
{
    parallel_for_(Range(0, dst.rows),
                 ResizeArea_Invoker<T, WT>(src, dst, xtab, xtab_size, ytab, ytab_size, tabofs),
                 dst.total()/((double)(1 << 16)));
}


typedef void (*ResizeFunc)( const Mat& src, Mat& dst,
                            const int* xofs, const void* alpha,
                            const int* yofs, const void* beta,
                            int xmin, int xmax, int ksize );

typedef void (*ResizeAreaFastFunc)( const Mat& src, Mat& dst,
                                    const int* ofs, const int *xofs,
                                    int scale_x, int scale_y );

typedef void (*ResizeAreaFunc)( const Mat& src, Mat& dst,
                                const DecimateAlpha* xtab, int xtab_size,
                                const DecimateAlpha* ytab, int ytab_size,
                                const int* yofs);


static int computeResizeAreaTab( int ssize, int dsize, int cn, double scale, DecimateAlpha* tab )
{
    int k = 0;
    for(int dx = 0; dx < dsize; dx++ )
    {
        double fsx1 = dx * scale;
        double fsx2 = fsx1 + scale;
        double cellWidth = std::min(scale, ssize - fsx1);

        int sx1 = cvCeil(fsx1), sx2 = cvFloor(fsx2);

        sx2 = std::min(sx2, ssize - 1);
        sx1 = std::min(sx1, sx2);

        if( sx1 - fsx1 > 1e-3 )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = (sx1 - 1) * cn;
            tab[k++].alpha = (float)((sx1 - fsx1) / cellWidth);
        }

        for(int sx = sx1; sx < sx2; sx++ )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = sx * cn;
            tab[k++].alpha = float(1.0 / cellWidth);
        }

        if( fsx2 - sx2 > 1e-3 )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = sx2 * cn;
            tab[k++].alpha = (float)(std::min(std::min(fsx2 - sx2, 1.), cellWidth) / cellWidth);
        }
    }
    return k;
}

#ifdef HAVE_OPENCL
static void ocl_computeResizeAreaTabs(int ssize, int dsize, double scale, int * const map_tab,
                                      float * const alpha_tab, int * const ofs_tab)
{
    int k = 0, dx = 0;
    for ( ; dx < dsize; dx++)
    {
        ofs_tab[dx] = k;

        double fsx1 = dx * scale;
        double fsx2 = fsx1 + scale;
        double cellWidth = std::min(scale, ssize - fsx1);

        int sx1 = cvCeil(fsx1), sx2 = cvFloor(fsx2);

        sx2 = std::min(sx2, ssize - 1);
        sx1 = std::min(sx1, sx2);

        if (sx1 - fsx1 > 1e-3)
        {
            map_tab[k] = sx1 - 1;
            alpha_tab[k++] = (float)((sx1 - fsx1) / cellWidth);
        }

        for (int sx = sx1; sx < sx2; sx++)
        {
            map_tab[k] = sx;
            alpha_tab[k++] = float(1.0 / cellWidth);
        }

        if (fsx2 - sx2 > 1e-3)
        {
            map_tab[k] = sx2;
            alpha_tab[k++] = (float)(std::min(std::min(fsx2 - sx2, 1.), cellWidth) / cellWidth);
        }
    }
    ofs_tab[dx] = k;
}

static bool ocl_resize( InputArray _src, OutputArray _dst, Size dsize,
                        double fx, double fy, int interpolation)
{
    int type = _src.type(), depth = CV_MAT_DEPTH(type), cn = CV_MAT_CN(type);

    double inv_fx = 1.0 / fx, inv_fy = 1.0 / fy;
    float inv_fxf = (float)inv_fx, inv_fyf = (float)inv_fy;
    int iscale_x = saturate_cast<int>(inv_fx), iscale_y = saturate_cast<int>(inv_fx);
    bool is_area_fast = std::abs(inv_fx - iscale_x) < DBL_EPSILON &&
        std::abs(inv_fy - iscale_y) < DBL_EPSILON;

    // in case of scale_x && scale_y is equal to 2
    // INTER_AREA (fast) also is equal to INTER_LINEAR
    if( interpolation == INTER_LINEAR && is_area_fast && iscale_x == 2 && iscale_y == 2 )
        /*interpolation = INTER_AREA*/(void)0; // INTER_AREA is slower

    if( !(cn <= 4 &&
           (interpolation == INTER_NEAREST || interpolation == INTER_LINEAR ||
            (interpolation == INTER_AREA && inv_fx >= 1 && inv_fy >= 1) )) )
        return false;

    UMat src = _src.getUMat();
    _dst.create(dsize, type);
    UMat dst = _dst.getUMat();

    Size ssize = src.size();
    ocl::Kernel k;
    size_t globalsize[] = { (size_t)dst.cols, (size_t)dst.rows };

    ocl::Image2D srcImage;

    // See if this could be done with a sampler.  We stick with integer
    // datatypes because the observed error is low.
    bool useSampler = (interpolation == INTER_LINEAR && ocl::Device::getDefault().imageSupport() &&
                       ocl::Image2D::canCreateAlias(src) && depth <= 4 &&
                       ocl::Image2D::isFormatSupported(depth, cn, true) &&
                       src.offset==0);
    if (useSampler)
    {
        int wdepth = std::max(depth, CV_32S);
        char buf[2][32];
        cv::String compileOpts = format("-D USE_SAMPLER -D depth=%d -D T=%s -D T1=%s "
                        "-D convertToDT=%s -D cn=%d",
                        depth, ocl::typeToStr(type), ocl::typeToStr(depth),
                        ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                        cn);
        k.create("resizeSampler", ocl::imgproc::resize_oclsrc, compileOpts);

        if (k.empty())
            useSampler = false;
        else
        {
            // Convert the input into an OpenCL image type, using normalized channel data types
            // and aliasing the UMat.
            srcImage = ocl::Image2D(src, true, true);
            k.args(srcImage, ocl::KernelArg::WriteOnly(dst),
                   (float)inv_fx, (float)inv_fy);
        }
    }

    if (interpolation == INTER_LINEAR && !useSampler)
    {
        char buf[2][32];

        // integer path is slower because of CPU part, so it's disabled
        if (depth == CV_8U && ((void)0, 0))
        {
            AutoBuffer<uchar> _buffer((dsize.width + dsize.height)*(sizeof(int) + sizeof(short)*2));
            int* xofs = (int*)(uchar*)_buffer, * yofs = xofs + dsize.width;
            short* ialpha = (short*)(yofs + dsize.height), * ibeta = ialpha + dsize.width*2;
            float fxx, fyy;
            int sx, sy;

            for (int dx = 0; dx < dsize.width; dx++)
            {
                fxx = (float)((dx+0.5)*inv_fx - 0.5);
                sx = cvFloor(fxx);
                fxx -= sx;

                if (sx < 0)
                    fxx = 0, sx = 0;

                if (sx >= ssize.width-1)
                    fxx = 0, sx = ssize.width-1;

                xofs[dx] = sx;
                ialpha[dx*2 + 0] = saturate_cast<short>((1.f - fxx) * INTER_RESIZE_COEF_SCALE);
                ialpha[dx*2 + 1] = saturate_cast<short>(fxx         * INTER_RESIZE_COEF_SCALE);
            }

            for (int dy = 0; dy < dsize.height; dy++)
            {
                fyy = (float)((dy+0.5)*inv_fy - 0.5);
                sy = cvFloor(fyy);
                fyy -= sy;

                yofs[dy] = sy;
                ibeta[dy*2 + 0] = saturate_cast<short>((1.f - fyy) * INTER_RESIZE_COEF_SCALE);
                ibeta[dy*2 + 1] = saturate_cast<short>(fyy         * INTER_RESIZE_COEF_SCALE);
            }

            int wdepth = std::max(depth, CV_32S), wtype = CV_MAKETYPE(wdepth, cn);
            UMat coeffs;
            Mat(1, static_cast<int>(_buffer.size()), CV_8UC1, (uchar *)_buffer).copyTo(coeffs);

            k.create("resizeLN", ocl::imgproc::resize_oclsrc,
                     format("-D INTER_LINEAR_INTEGER -D depth=%d -D T=%s -D T1=%s "
                            "-D WT=%s -D convertToWT=%s -D convertToDT=%s -D cn=%d "
                            "-D INTER_RESIZE_COEF_BITS=%d",
                            depth, ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                            ocl::convertTypeStr(depth, wdepth, cn, buf[0]),
                            ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                            cn, INTER_RESIZE_COEF_BITS));
            if (k.empty())
                return false;

            k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
                   ocl::KernelArg::PtrReadOnly(coeffs));
        }
        else
        {
            int wdepth = std::max(depth, CV_32S), wtype = CV_MAKETYPE(wdepth, cn);
            k.create("resizeLN", ocl::imgproc::resize_oclsrc,
                     format("-D INTER_LINEAR -D depth=%d -D T=%s -D T1=%s "
                            "-D WT=%s -D convertToWT=%s -D convertToDT=%s -D cn=%d "
                            "-D INTER_RESIZE_COEF_BITS=%d",
                            depth, ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                            ocl::convertTypeStr(depth, wdepth, cn, buf[0]),
                            ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                            cn, INTER_RESIZE_COEF_BITS));
            if (k.empty())
                return false;

            k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
                   (float)inv_fx, (float)inv_fy);
        }
    }
    else if (interpolation == INTER_NEAREST)
    {
        k.create("resizeNN", ocl::imgproc::resize_oclsrc,
                 format("-D INTER_NEAREST -D T=%s -D T1=%s -D cn=%d",
                        ocl::vecopTypeToStr(type), ocl::vecopTypeToStr(depth), cn));
        if (k.empty())
            return false;

        k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
               (float)inv_fx, (float)inv_fy);
    }
    else if (interpolation == INTER_AREA)
    {
        int wdepth = std::max(depth, is_area_fast ? CV_32S : CV_32F);
        int wtype = CV_MAKE_TYPE(wdepth, cn);

        char cvt[2][40];
        String buildOption = format("-D INTER_AREA -D T=%s -D T1=%s -D WTV=%s -D convertToWTV=%s -D cn=%d",
                                    ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                                    ocl::convertTypeStr(depth, wdepth, cn, cvt[0]), cn);

        UMat alphaOcl, tabofsOcl, mapOcl;
        UMat dmap, smap;

        if (is_area_fast)
        {
            int wdepth2 = std::max(CV_32F, depth), wtype2 = CV_MAKE_TYPE(wdepth2, cn);
            buildOption = buildOption + format(" -D convertToT=%s -D WT2V=%s -D convertToWT2V=%s -D INTER_AREA_FAST"
                                                " -D XSCALE=%d -D YSCALE=%d -D SCALE=%ff",
                                                ocl::convertTypeStr(wdepth2, depth, cn, cvt[0]),
                                                ocl::typeToStr(wtype2), ocl::convertTypeStr(wdepth, wdepth2, cn, cvt[1]),
                                    iscale_x, iscale_y, 1.0f / (iscale_x * iscale_y));

            k.create("resizeAREA_FAST", ocl::imgproc::resize_oclsrc, buildOption);
            if (k.empty())
                return false;
        }
        else
        {
            buildOption = buildOption + format(" -D convertToT=%s", ocl::convertTypeStr(wdepth, depth, cn, cvt[0]));
            k.create("resizeAREA", ocl::imgproc::resize_oclsrc, buildOption);
            if (k.empty())
                return false;

            int xytab_size = (ssize.width + ssize.height) << 1;
            int tabofs_size = dsize.height + dsize.width + 2;

            AutoBuffer<int> _xymap_tab(xytab_size), _xyofs_tab(tabofs_size);
            AutoBuffer<float> _xyalpha_tab(xytab_size);
            int * xmap_tab = _xymap_tab, * ymap_tab = _xymap_tab + (ssize.width << 1);
            float * xalpha_tab = _xyalpha_tab, * yalpha_tab = _xyalpha_tab + (ssize.width << 1);
            int * xofs_tab = _xyofs_tab, * yofs_tab = _xyofs_tab + dsize.width + 1;

            ocl_computeResizeAreaTabs(ssize.width, dsize.width, inv_fx, xmap_tab, xalpha_tab, xofs_tab);
            ocl_computeResizeAreaTabs(ssize.height, dsize.height, inv_fy, ymap_tab, yalpha_tab, yofs_tab);

            // loading precomputed arrays to GPU
            Mat(1, xytab_size, CV_32FC1, (void *)_xyalpha_tab).copyTo(alphaOcl);
            Mat(1, xytab_size, CV_32SC1, (void *)_xymap_tab).copyTo(mapOcl);
            Mat(1, tabofs_size, CV_32SC1, (void *)_xyofs_tab).copyTo(tabofsOcl);
        }

        ocl::KernelArg srcarg = ocl::KernelArg::ReadOnly(src), dstarg = ocl::KernelArg::WriteOnly(dst);

        if (is_area_fast)
            k.args(srcarg, dstarg);
        else
            k.args(srcarg, dstarg, inv_fxf, inv_fyf, ocl::KernelArg::PtrReadOnly(tabofsOcl),
                   ocl::KernelArg::PtrReadOnly(mapOcl), ocl::KernelArg::PtrReadOnly(alphaOcl));

        return k.run(2, globalsize, NULL, false);
    }

    return k.run(2, globalsize, 0, false);
}

#endif

#ifdef HAVE_IPP
#define IPP_RESIZE_PARALLEL 1

#ifdef HAVE_IPP_IW
class ipp_resizeParallel: public ParallelLoopBody
{
public:
    ipp_resizeParallel(::ipp::IwiImage &src, ::ipp::IwiImage &dst, bool &ok):
        m_src(src), m_dst(dst), m_ok(ok) {}
    ~ipp_resizeParallel()
    {
    }

    void Init(IppiInterpolationType inter)
    {
        iwiResize.InitAlloc(m_src.m_size, m_dst.m_size, m_src.m_dataType, m_src.m_channels, inter, ::ipp::IwiResizeParams(0, 0, 0.75, 4), ippBorderRepl);

        m_ok = true;
    }

    virtual void operator() (const Range& range) const
    {
        CV_INSTRUMENT_REGION_IPP()

        if(!m_ok)
            return;

        try
        {
            ::ipp::IwiTile tile = ::ipp::IwiRoi(0, range.start, m_dst.m_size.width, range.end - range.start);
            CV_INSTRUMENT_FUN_IPP(iwiResize, m_src, m_dst, ippBorderRepl, tile);
        }
        catch(::ipp::IwException)
        {
            m_ok = false;
            return;
        }
    }
private:
    ::ipp::IwiImage &m_src;
    ::ipp::IwiImage &m_dst;

    mutable ::ipp::IwiResize iwiResize;

    volatile bool &m_ok;
    const ipp_resizeParallel& operator= (const ipp_resizeParallel&);
};

class ipp_resizeAffineParallel: public ParallelLoopBody
{
public:
    ipp_resizeAffineParallel(::ipp::IwiImage &src, ::ipp::IwiImage &dst, bool &ok):
        m_src(src), m_dst(dst), m_ok(ok) {}
    ~ipp_resizeAffineParallel()
    {
    }

    void Init(IppiInterpolationType inter, double scaleX, double scaleY)
    {
        double shift = (inter == ippNearest)?-1e-10:-0.5;
        double coeffs[2][3] = {
            {scaleX, 0,      shift+0.5*scaleX},
            {0,      scaleY, shift+0.5*scaleY}
        };

        iwiWarpAffine.InitAlloc(m_src.m_size, m_dst.m_size, m_src.m_dataType, m_src.m_channels, coeffs, iwTransForward, inter, ::ipp::IwiWarpAffineParams(0, 0, 0.75), ippBorderRepl);

        m_ok = true;
    }

    virtual void operator() (const Range& range) const
    {
        CV_INSTRUMENT_REGION_IPP()

        if(!m_ok)
            return;

        try
        {
            ::ipp::IwiTile tile = ::ipp::IwiRoi(0, range.start, m_dst.m_size.width, range.end - range.start);
            CV_INSTRUMENT_FUN_IPP(iwiWarpAffine, m_src, m_dst, tile);
        }
        catch(::ipp::IwException)
        {
            m_ok = false;
            return;
        }
    }
private:
    ::ipp::IwiImage &m_src;
    ::ipp::IwiImage &m_dst;

    mutable ::ipp::IwiWarpAffine iwiWarpAffine;

    volatile bool &m_ok;
    const ipp_resizeAffineParallel& operator= (const ipp_resizeAffineParallel&);
};
#endif

static bool ipp_resize(const uchar * src_data, size_t src_step, int src_width, int src_height,
            uchar * dst_data, size_t dst_step, int dst_width, int dst_height, double inv_scale_x, double inv_scale_y,
            int depth, int channels, int interpolation)
{
#ifdef HAVE_IPP_IW
    CV_INSTRUMENT_REGION_IPP()

    IppDataType           ippDataType = ippiGetDataType(depth);
    IppiInterpolationType ippInter    = ippiGetInterpolation(interpolation);
    if(ippInter < 0)
        return false;

    // Resize which doesn't match OpenCV exactly
    if (!cv::ipp::useIPP_NE())
    {
        if (ippInter == ippNearest || ippInter == ippSuper || (ippDataType == ipp8u && ippInter == ippLinear))
            return false;
    }

    if(ippInter != ippLinear && ippDataType == ipp64f)
        return false;

#if IPP_VERSION_X100 < 201801
    // Degradations on int^2 linear downscale
    if (ippDataType != ipp64f && ippInter == ippLinear && inv_scale_x < 1 && inv_scale_y < 1) // if downscale
    {
        int scale_x = (int)(1 / inv_scale_x);
        int scale_y = (int)(1 / inv_scale_y);
        if (1 / inv_scale_x - scale_x < DBL_EPSILON && 1 / inv_scale_y - scale_y < DBL_EPSILON) // if integer
        {
            if (!(scale_x&(scale_x - 1)) && !(scale_y&(scale_y - 1))) // if power of 2
                return false;
        }
    }
#endif

    bool  affine = false;
    const double IPP_RESIZE_EPS = (depth == CV_64F)?0:1e-10;
    double ex = fabs((double)dst_width / src_width  - inv_scale_x) / inv_scale_x;
    double ey = fabs((double)dst_height / src_height - inv_scale_y) / inv_scale_y;

    // Use affine transform resize to allow sub-pixel accuracy
    if(ex > IPP_RESIZE_EPS || ey > IPP_RESIZE_EPS)
        affine = true;

    // Affine doesn't support Lanczos and Super interpolations
    if(affine && (ippInter == ippLanczos || ippInter == ippSuper))
        return false;

    try
    {
        ::ipp::IwiImage iwSrc(::ipp::IwiSize(src_width, src_height), ippDataType, channels, 0, (void*)src_data, src_step);
        ::ipp::IwiImage iwDst(::ipp::IwiSize(dst_width, dst_height), ippDataType, channels, 0, (void*)dst_data, dst_step);

        bool  ok;
        int   threads = ippiSuggestThreadsNum(iwDst, 1+((double)(src_width*src_height)/(dst_width*dst_height)));
        Range range(0, dst_height);
        ipp_resizeParallel       invokerGeneral(iwSrc, iwDst, ok);
        ipp_resizeAffineParallel invokerAffine(iwSrc, iwDst, ok);
        ParallelLoopBody        *pInvoker = NULL;
        if(affine)
        {
            pInvoker = &invokerAffine;
            invokerAffine.Init(ippInter, inv_scale_x, inv_scale_y);
        }
        else
        {
            pInvoker = &invokerGeneral;
            invokerGeneral.Init(ippInter);
        }

        if(IPP_RESIZE_PARALLEL && threads > 1)
            parallel_for_(range, *pInvoker, threads*4);
        else
            pInvoker->operator()(range);

        if(!ok)
            return false;
    }
    catch(::ipp::IwException)
    {
        return false;
    }
    return true;
#else
    CV_UNUSED(src_data); CV_UNUSED(src_step); CV_UNUSED(src_width); CV_UNUSED(src_height); CV_UNUSED(dst_data); CV_UNUSED(dst_step);
    CV_UNUSED(dst_width); CV_UNUSED(dst_height); CV_UNUSED(inv_scale_x); CV_UNUSED(inv_scale_y); CV_UNUSED(depth);
    CV_UNUSED(channels); CV_UNUSED(interpolation);
    return false;
#endif
}
#endif

//==================================================================================================

namespace hal {

void resize(int src_type,
            const uchar * src_data, size_t src_step, int src_width, int src_height,
            uchar * dst_data, size_t dst_step, int dst_width, int dst_height,
            double inv_scale_x, double inv_scale_y, int interpolation)
{
    CV_INSTRUMENT_REGION()

    CV_Assert((dst_width * dst_height > 0) || (inv_scale_x > 0 && inv_scale_y > 0));
    if (inv_scale_x < DBL_EPSILON || inv_scale_y < DBL_EPSILON)
    {
        inv_scale_x = static_cast<double>(dst_width) / src_width;
        inv_scale_y = static_cast<double>(dst_height) / src_height;
    }

    CALL_HAL(resize, cv_hal_resize, src_type, src_data, src_step, src_width, src_height, dst_data, dst_step, dst_width, dst_height, inv_scale_x, inv_scale_y, interpolation);

    int  depth = CV_MAT_DEPTH(src_type), cn = CV_MAT_CN(src_type);
    Size dsize = Size(saturate_cast<int>(src_width*inv_scale_x),
                        saturate_cast<int>(src_height*inv_scale_y));
    CV_Assert( dsize.area() > 0 );

    CV_IPP_RUN_FAST(ipp_resize(src_data, src_step, src_width, src_height, dst_data, dst_step, dsize.width, dsize.height, inv_scale_x, inv_scale_y, depth, cn, interpolation))

    static ResizeFunc linear_tab[] =
    {
        resizeGeneric_<
            HResizeLinear<uchar, int, short,
                INTER_RESIZE_COEF_SCALE,
                HResizeLinearVec_8u32s>,
            VResizeLinear<uchar, int, short,
                FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
                VResizeLinearVec_32s8u> >,
        0,
        resizeGeneric_<
            HResizeLinear<ushort, float, float, 1,
                HResizeLinearVec_16u32f>,
            VResizeLinear<ushort, float, float, Cast<float, ushort>,
                VResizeLinearVec_32f16u> >,
        resizeGeneric_<
            HResizeLinear<short, float, float, 1,
                HResizeLinearVec_16s32f>,
            VResizeLinear<short, float, float, Cast<float, short>,
                VResizeLinearVec_32f16s> >,
        0,
        resizeGeneric_<
            HResizeLinear<float, float, float, 1,
                HResizeLinearVec_32f>,
            VResizeLinear<float, float, float, Cast<float, float>,
                VResizeLinearVec_32f> >,
        resizeGeneric_<
            HResizeLinear<double, double, float, 1,
                HResizeNoVec>,
            VResizeLinear<double, double, float, Cast<double, double>,
                VResizeNoVec> >,
        0
    };

    static ResizeFunc cubic_tab[] =
    {
        resizeGeneric_<
            HResizeCubic<uchar, int, short>,
            VResizeCubic<uchar, int, short,
                FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
                VResizeCubicVec_32s8u> >,
        0,
        resizeGeneric_<
            HResizeCubic<ushort, float, float>,
            VResizeCubic<ushort, float, float, Cast<float, ushort>,
            VResizeCubicVec_32f16u> >,
        resizeGeneric_<
            HResizeCubic<short, float, float>,
            VResizeCubic<short, float, float, Cast<float, short>,
            VResizeCubicVec_32f16s> >,
        0,
        resizeGeneric_<
            HResizeCubic<float, float, float>,
            VResizeCubic<float, float, float, Cast<float, float>,
            VResizeCubicVec_32f> >,
        resizeGeneric_<
            HResizeCubic<double, double, float>,
            VResizeCubic<double, double, float, Cast<double, double>,
            VResizeNoVec> >,
        0
    };

    static ResizeFunc lanczos4_tab[] =
    {
        resizeGeneric_<HResizeLanczos4<uchar, int, short>,
            VResizeLanczos4<uchar, int, short,
            FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
            VResizeNoVec> >,
        0,
        resizeGeneric_<HResizeLanczos4<ushort, float, float>,
            VResizeLanczos4<ushort, float, float, Cast<float, ushort>,
            VResizeLanczos4Vec_32f16u> >,
        resizeGeneric_<HResizeLanczos4<short, float, float>,
            VResizeLanczos4<short, float, float, Cast<float, short>,
            VResizeLanczos4Vec_32f16s> >,
        0,
        resizeGeneric_<HResizeLanczos4<float, float, float>,
            VResizeLanczos4<float, float, float, Cast<float, float>,
            VResizeLanczos4Vec_32f> >,
        resizeGeneric_<HResizeLanczos4<double, double, float>,
            VResizeLanczos4<double, double, float, Cast<double, double>,
            VResizeNoVec> >,
        0
    };

    static ResizeAreaFastFunc areafast_tab[] =
    {
        resizeAreaFast_<uchar, int, ResizeAreaFastVec<uchar, ResizeAreaFastVec_SIMD_8u> >,
        0,
        resizeAreaFast_<ushort, float, ResizeAreaFastVec<ushort, ResizeAreaFastVec_SIMD_16u> >,
        resizeAreaFast_<short, float, ResizeAreaFastVec<short, ResizeAreaFastVec_SIMD_16s> >,
        0,
        resizeAreaFast_<float, float, ResizeAreaFastVec_SIMD_32f>,
        resizeAreaFast_<double, double, ResizeAreaFastNoVec<double, double> >,
        0
    };

    static ResizeAreaFunc area_tab[] =
    {
        resizeArea_<uchar, float>, 0, resizeArea_<ushort, float>,
        resizeArea_<short, float>, 0, resizeArea_<float, float>,
        resizeArea_<double, double>, 0
    };

    double scale_x = 1./inv_scale_x, scale_y = 1./inv_scale_y;

    int iscale_x = saturate_cast<int>(scale_x);
    int iscale_y = saturate_cast<int>(scale_y);

    bool is_area_fast = std::abs(scale_x - iscale_x) < DBL_EPSILON &&
            std::abs(scale_y - iscale_y) < DBL_EPSILON;

    Mat src(Size(src_width, src_height), src_type, const_cast<uchar*>(src_data), src_step);
    Mat dst(dsize, src_type, dst_data, dst_step);

    if( interpolation == INTER_NEAREST )
    {
        resizeNN( src, dst, inv_scale_x, inv_scale_y );
        return;
    }

    int k, sx, sy, dx, dy;


    {
        // in case of scale_x && scale_y is equal to 2
        // INTER_AREA (fast) also is equal to INTER_LINEAR
        if( interpolation == INTER_LINEAR && is_area_fast && iscale_x == 2 && iscale_y == 2 )
            interpolation = INTER_AREA;

        // true "area" interpolation is only implemented for the case (scale_x <= 1 && scale_y <= 1).
        // In other cases it is emulated using some variant of bilinear interpolation
        if( interpolation == INTER_AREA && scale_x >= 1 && scale_y >= 1 )
        {
            if( is_area_fast )
            {
                int area = iscale_x*iscale_y;
                size_t srcstep = src_step / src.elemSize1();
                AutoBuffer<int> _ofs(area + dsize.width*cn);
                int* ofs = _ofs;
                int* xofs = ofs + area;
                ResizeAreaFastFunc func = areafast_tab[depth];
                CV_Assert( func != 0 );

                for( sy = 0, k = 0; sy < iscale_y; sy++ )
                    for( sx = 0; sx < iscale_x; sx++ )
                        ofs[k++] = (int)(sy*srcstep + sx*cn);

                for( dx = 0; dx < dsize.width; dx++ )
                {
                    int j = dx * cn;
                    sx = iscale_x * j;
                    for( k = 0; k < cn; k++ )
                        xofs[j + k] = sx + k;
                }

                func( src, dst, ofs, xofs, iscale_x, iscale_y );
                return;
            }

            ResizeAreaFunc func = area_tab[depth];
            CV_Assert( func != 0 && cn <= 4 );

            AutoBuffer<DecimateAlpha> _xytab((src_width + src_height)*2);
            DecimateAlpha* xtab = _xytab, *ytab = xtab + src_width*2;

            int xtab_size = computeResizeAreaTab(src_width, dsize.width, cn, scale_x, xtab);
            int ytab_size = computeResizeAreaTab(src_height, dsize.height, 1, scale_y, ytab);

            AutoBuffer<int> _tabofs(dsize.height + 1);
            int* tabofs = _tabofs;
            for( k = 0, dy = 0; k < ytab_size; k++ )
            {
                if( k == 0 || ytab[k].di != ytab[k-1].di )
                {
                    assert( ytab[k].di == dy );
                    tabofs[dy++] = k;
                }
            }
            tabofs[dy] = ytab_size;

            func( src, dst, xtab, xtab_size, ytab, ytab_size, tabofs );
            return;
        }
    }

    int xmin = 0, xmax = dsize.width, width = dsize.width*cn;
    bool area_mode = interpolation == INTER_AREA;
    bool fixpt = depth == CV_8U;
    float fx, fy;
    ResizeFunc func=0;
    int ksize=0, ksize2;
    if( interpolation == INTER_CUBIC )
        ksize = 4, func = cubic_tab[depth];
    else if( interpolation == INTER_LANCZOS4 )
        ksize = 8, func = lanczos4_tab[depth];
    else if( interpolation == INTER_LINEAR || interpolation == INTER_AREA )
        ksize = 2, func = linear_tab[depth];
    else
        CV_Error( CV_StsBadArg, "Unknown interpolation method" );
    ksize2 = ksize/2;

    CV_Assert( func != 0 );

    AutoBuffer<uchar> _buffer((width + dsize.height)*(sizeof(int) + sizeof(float)*ksize));
    int* xofs = (int*)(uchar*)_buffer;
    int* yofs = xofs + width;
    float* alpha = (float*)(yofs + dsize.height);
    short* ialpha = (short*)alpha;
    float* beta = alpha + width*ksize;
    short* ibeta = ialpha + width*ksize;
    float cbuf[MAX_ESIZE];

    for( dx = 0; dx < dsize.width; dx++ )
    {
        if( !area_mode )
        {
            fx = (float)((dx+0.5)*scale_x - 0.5);
            sx = cvFloor(fx);
            fx -= sx;
        }
        else
        {
            sx = cvFloor(dx*scale_x);
            fx = (float)((dx+1) - (sx+1)*inv_scale_x);
            fx = fx <= 0 ? 0.f : fx - cvFloor(fx);
        }

        if( sx < ksize2-1 )
        {
            xmin = dx+1;
            if( sx < 0 && (interpolation != INTER_CUBIC && interpolation != INTER_LANCZOS4))
                fx = 0, sx = 0;
        }

        if( sx + ksize2 >= src_width )
        {
            xmax = std::min( xmax, dx );
            if( sx >= src_width-1 && (interpolation != INTER_CUBIC && interpolation != INTER_LANCZOS4))
                fx = 0, sx = src_width-1;
        }

        for( k = 0, sx *= cn; k < cn; k++ )
            xofs[dx*cn + k] = sx + k;

        if( interpolation == INTER_CUBIC )
            interpolateCubic( fx, cbuf );
        else if( interpolation == INTER_LANCZOS4 )
            interpolateLanczos4( fx, cbuf );
        else
        {
            cbuf[0] = 1.f - fx;
            cbuf[1] = fx;
        }
        if( fixpt )
        {
            for( k = 0; k < ksize; k++ )
                ialpha[dx*cn*ksize + k] = saturate_cast<short>(cbuf[k]*INTER_RESIZE_COEF_SCALE);
            for( ; k < cn*ksize; k++ )
                ialpha[dx*cn*ksize + k] = ialpha[dx*cn*ksize + k - ksize];
        }
        else
        {
            for( k = 0; k < ksize; k++ )
                alpha[dx*cn*ksize + k] = cbuf[k];
            for( ; k < cn*ksize; k++ )
                alpha[dx*cn*ksize + k] = alpha[dx*cn*ksize + k - ksize];
        }
    }

    for( dy = 0; dy < dsize.height; dy++ )
    {
        if( !area_mode )
        {
            fy = (float)((dy+0.5)*scale_y - 0.5);
            sy = cvFloor(fy);
            fy -= sy;
        }
        else
        {
            sy = cvFloor(dy*scale_y);
            fy = (float)((dy+1) - (sy+1)*inv_scale_y);
            fy = fy <= 0 ? 0.f : fy - cvFloor(fy);
        }

        yofs[dy] = sy;
        if( interpolation == INTER_CUBIC )
            interpolateCubic( fy, cbuf );
        else if( interpolation == INTER_LANCZOS4 )
            interpolateLanczos4( fy, cbuf );
        else
        {
            cbuf[0] = 1.f - fy;
            cbuf[1] = fy;
        }

        if( fixpt )
        {
            for( k = 0; k < ksize; k++ )
                ibeta[dy*ksize + k] = saturate_cast<short>(cbuf[k]*INTER_RESIZE_COEF_SCALE);
        }
        else
        {
            for( k = 0; k < ksize; k++ )
                beta[dy*ksize + k] = cbuf[k];
        }
    }

    func( src, dst, xofs, fixpt ? (void*)ialpha : (void*)alpha, yofs,
          fixpt ? (void*)ibeta : (void*)beta, xmin, xmax, ksize );
}

} // cv::hal::
} // cv::

//==================================================================================================

void cv::resize( InputArray _src, OutputArray _dst, Size dsize,
                 double inv_scale_x, double inv_scale_y, int interpolation )
{
    CV_INSTRUMENT_REGION()

    Size ssize = _src.size();

    CV_Assert( ssize.width > 0 && ssize.height > 0 );
    CV_Assert( dsize.area() > 0 || (inv_scale_x > 0 && inv_scale_y > 0) );
    if( dsize.area() == 0 )
    {
        dsize = Size(saturate_cast<int>(ssize.width*inv_scale_x),
                     saturate_cast<int>(ssize.height*inv_scale_y));
        CV_Assert( dsize.area() > 0 );
    }
    else
    {
        inv_scale_x = (double)dsize.width/ssize.width;
        inv_scale_y = (double)dsize.height/ssize.height;
    }

    CV_OCL_RUN(_src.dims() <= 2 && _dst.isUMat() && _src.cols() > 10 && _src.rows() > 10,
               ocl_resize(_src, _dst, dsize, inv_scale_x, inv_scale_y, interpolation))

    Mat src = _src.getMat();
    _dst.create(dsize, src.type());
    Mat dst = _dst.getMat();

    if (dsize == ssize)
    {
        // Source and destination are of same size. Use simple copy.
        src.copyTo(dst);
        return;
    }

    hal::resize(src.type(), src.data, src.step, src.cols, src.rows, dst.data, dst.step, dst.cols, dst.rows, inv_scale_x, inv_scale_y, interpolation);
}


CV_IMPL void
cvResize( const CvArr* srcarr, CvArr* dstarr, int method )
{
    cv::Mat src = cv::cvarrToMat(srcarr), dst = cv::cvarrToMat(dstarr);
    CV_Assert( src.type() == dst.type() );
    cv::resize( src, dst, dst.size(), (double)dst.cols/src.cols,
        (double)dst.rows/src.rows, method );
}

/* End of file. */
